New Approach of Transforming Lumped Element Circuit of ... - IJENS

International Journal of Engineering & Computer Science IJECS-IJENS Vol:13 No:03

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New Approach of Transforming Lumped Element Circuit of High-order Chebyshev Low Pass Filter Into Microstrip Line Form Liew Hui Fang , Syed Idris Syed Hassan, Mohd Fareq Bin Abd. Malek, Yufridin Bin Wahab and Norshafinash Binti Saudin Abstract — A new approach of transforming lumped elements circuit into microstrip line for all high-order Chebyshev low pass filter is presented. The high-order Chebyshev low pass filter operating within UHF range have been designed, simulated and implemented on FR4 substrate for order N=3,4,5,6,7,8,9 with a band pass ripple of 0.01dB. The circuits were simulated and developed using Advanced Design S oftware (ADS )for both lumped and microstrip filter. Correction factor has been considered due to fringing inductor and capacitor. From ADS simulation results show that the response of microstrip line circuit of Chebyshev low pass filter with fringing correction factor has an excellent agreement with its lumped circuit. This shows that the new approach of transforming lumped element circuit into microstrip line is able to solve the design of high order Chebyshev low pass filter into microstrip line. Index Term— Microstrip line circuit; Harmonic Filter; Microwave communication; Chebyshev low pass filter. I. INT RODUCTION The conventional lo w pass filter always faces the problem of converting the lu mped circuit prototype into microstrip when the number of order, N, is increasing and the circuit also become larger and complexity. The advantage of lumped element circuits are it is having s maller size, lower cost, and wider bandwidth characteristics and the Q factor is generally lower than distributed circuits. As the operating frequency moves into higher spectrum, the distributed circuit is more preferable though it has a higher Q factor, and thus it is usually used for high-frequency applications and lumped elements are having disadvantage of zero-d imensional by definition. In other words, the lumped elements have no physical dimensions and hard to design which are significant with respect to the wavelength at the operating frequency, so that the phase shift that arises can be ignored. Discrete lu mped elements are conventionally used in electronic circuits that work at a lower frequency and sizes of the discrete lumped elements become comparable at these frequencies. [1] T his work was supported in part by the University Malaysia Perlis and the Malaysian Ministry of Higher Education for providing the Fundamental Research Grant Scheme (FRGS Grant No: 9011-00011). Liew Hui Fang and Yufridin Wahab are with the School of Microelectronics Engineering, University Malaysia Perlis (e-mail: [email protected], [email protected]). Syed Idris Syed Hassan, MohdFareq Bin Abd. Malek,and Norshafinash Saudin are with the School of Electrical System Engineering, University Malaysia Perlis (e-mail: [email protected], [email protected], [email protected]).

Modern RF and microwave co mmunication systems, specifically mobile and satellite commun ications required high performance narrow band filters with linear phase[2][3]. There are some of tools co mmonly suitable used to design and optimize RF sub-component and systems, especially in microstrip filters in variety micro wave system such as radars, satellite system, test system and measurement o r electronics war to transfer energy in one or mo re pass band and to weaken the power in one or mo re cut band is used very high[2],[3]. In previous work on wireless communicat ions, Omid Borazjan i and Arman Rezaee[4] recommend that design of microstrip low pass filter was designed in stepped impedance method in wh ich the alternative part characteristic linear impedance such as length and width are desired by stimu lated using of HFSS software and relying on full wave analytical methods in three dimensional technology. Their based on odd order (N-5) o f ripp le 0.2dBfor Chebyshev low pass filter using the ABCD network parameters method. The circuit was simulated and analyzed using planar electro magnetic simu lator, Sonnet V12.56.In the design, the first capacitor is in shunt connection and followed by inductor in series connection. Based on Sudipta Das and Dr. S.K. Chowdhurywork[5], microtsrip line filters are designed in variety type of method to achieve the large bandwidth and smaller device size. Filter was realized in microstrip line of only even order and odd order where N=3&6 and ripple 0.1dB are selected. They applied impedance characteristic method, and fo llo wed by determining the length and width of microstrip line fo r each capacitor and inductor. The design and simulat ion were performed using 3D full wave method of mo ment based on electromagnetic simulator IE3D and the response of filter was verified using the program code in MATLAB in order to obtain microstrip line lo w pass filter for S-band response. For practical b roadband microstrip filter design and implementation method, Abdullah Eroglu, Tracy Cline and Bil Westrick [6]have suggested that in practical analytical method of using ABCD network parameter to design a broadband microstrip line filters. The method significant facilities the design process and gives accurate result. [6]The microstrip filter is design using 5 order chebyshev low pass filter with specifications and simu lated with planar electro magnetic simu lator, Sonnet V12.56 wh ich operating at 1.5GHz bandwidth. Filter has important imp licat ion for impedance matching and frequency selectivity, which great ly impact RF receiver performance such as noise and power consumption. In order to obtain mo re accurate in frequency response on return loss and insertion loss, the lumped element lo w pass filter circuits proposed to convert

135903-7272-IJECS-IJENS © June 2013 IJENS

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International Journal of Engineering & Computer Science IJECS-IJENS Vol:13 No:03 the circuit into the stepped impedance microstrip line. They worked on using CAD tools to design better performing circuit and integrated systems on RF and micro wave circuit designed. They also mentioned that for electronic design automation (EDA) and electro magnetic (EM ) analysis software and MALTAB also using for compute the insertion loss and return low of filter responses. This ABCD parameter method suitable for design low cost broadband microstrip filters with h igh accuracy. Navita Singh, Saurabh Dhiman, Prena Jain and Tanmay Bhardwaj [8] state that ,microstrip line is a good candidates for filters design due to its advantages of low cost, compact size, light weight, planar structure and easy integration with other components on a single boards. They develop the stepped impedance micro wave low pass filter by using microstrip line working at 3.7GHz and for order N-3 with band pass ripple 0.1dB. The development of microstrip line filter are simu lated by using IE3D simu lator software and observed frequency responses by using 3D full wave EM simu lated performance. [8] They apply low pass filter is design based on high optimized for high performance and efficient. The microstrip technology is used for simp licity and ease of fabrication. The main purpose of microstrip technology an advance way to obtain filter with maximu m reduction in wh ich each filter‟s lu mped co mponents is realized as microstrip transmission line. Benefits of microstrip filter in transmission line is compact nature minimizes required space for realization and its suitable for integration within in wireless system application. [7] In most works, the method of calculat ing accurate dimension of microstrip has not been shown comprehensively. May be the authors used simp le method and then optimized the dimension using software simulat ion. This will totally change the properties of Chebyshev filter. In this paper, a new approach method of t ransforming lu mped circuit into microtsrip line is suggested to introducing correction factor due to fringing so that accurate dimension can be determined without changing the properties of the Chebyshev filter. II. M ICROST RIP LINE DESIGN TECHNIQUES The design of Chebyshev low pass filter involved two main steps. First is to identify the appro ximated lo w pass filter prototype. The design involved in choosing number of react ive element and pass band ripples wh ich depend on required specification. The elements‟ value of the low pass prototype filter are usually normalized to a source impedance =1and cut off frequency =1.0 .The prototype is transformed into the L-C elements for the desired cutoff frequency and the desired source impedance , which is normally 50 oh ms for microstrip line filter [5]. The main step should be considered is the design of microstrip line lo w pass filters into appropriate microstrip realization of the lu mped elements filters [8]. The specification of the filters fo r the lo w pass prototype are the ripple factor of = 0.01dB. Impedance source / load = 50 oh ms, the normalized value ie. , , , ….. , fro m Table 1andthe filter is assumed to be fabricated on a FR4substrate.[9] The characteristic impedance for inductance was taken to be 100 ohm and the capacitance of 20 ohm. After determining the prototype of the low pass filter fro m

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Table 1 for N=3, 4, 5, 6, 7, 8, 9, the values of inductance and capacitance were calculated using Equation (1), (2) whereas inductor in series connection and capacitor in parallel connection. T ABLE I CHEBYSHEV 0.01DB EQUAL RIPPLE (RLF-26.4DB) [10]

= = / where = 2π

)/ )

(1) (2)

The filter schematic diagram is shown in Figure 1

Fig. 1. Schematic diagram of Chebyshev filters for N-5

In order to convert into microstrip line, the inductance L with its fringing capacitor is modeled as π-network as shown in Figure 2.

Fig. 2. Model for series inductor with fringing capacitors

Capacitance C with fringing inductance is modeled as T-network as shown in Fig. 3.

Fig. 3. Model for shunt capacitor with fringing inductors

For inductance L, the length of microstrip with characteristic impedance ZOL =100 ohm can be calculated using Equation (3)


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 L  d  sin 1  2  Z oL 

dL 

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(3) All these fringing capacitance and inductance are calculated using Equation 4 and 6 respectively

And it‟s fringing capacitor as C fL 

 d  tan  Z oL  d  1

(4)

For capacitor, C, the length of microstrip with characteristic impedance ZOC=25 ohm can be calculated using Equation (5)

dC 

d sin 1  CZ oC  2

(5)

And the fringing inductance as

L fC  When,

 d  tan L    d 

Z oC

d 

(6) Fig. 4. Chebyshev Low pass filters N-5 from Fig. 1with fringing

By considering the fringing, the new value of L1 , L2 , L3 , C1 and C2 are :-

c f

r

(7)

L1n  L1 

L fC1 2 L fC1

Where

L2 n  L2 

d = wavelength С=wavelength of light -3.0e8 =dielectric constants

L3n  L3 

2

C1n  C1 

C fL = fringing capacitance

C2 n  C2 

L fC = fringing inductance The microstrip line width for capacitor and inductor is calculated using the following formula (approximation)

Zo 

377  wn   1.57  r  h 

 377  wn    1.57 h Z  r  

(8)



L fC 2 2

L fC 2

d C = length of fringing capacitance d L= length of fringing inductance

(10)

2 C fL1 2 L fC 2 2

(11)

(12)



L fC 2



2 L fC 3 2

(13) (14)

Thus the circuit with the new values is shown in Fig. 5. The length of microstrip for inductor and capacitor are calculated using Equation (3) and (5), respectively based on these new values.

(9)

Where W n referred to W 100 , W 50 , W 25 and Z referred to ZoL ,ZoC&Zo When applying to the circuit in Fig 1 , the fringing will be adding to the circuit as shown in Fig 4. Where Lfc1 = fringing inductance due to capacitor C1 Lfc2 = fringing inductance due to capacitor C2 CfL1 = fringing capacitance due to inductor L1 CfL2 =fringing capacitance due to inductor L2 CfL3 =fringing capacitance due to inductor L3

Fig. 5. Chebyshev low pass filters N-5 from Fig. 1

III. A DS SIMULAT ION A ND RESULT To verify this approach whether it is satisfied or not , we simu late three types ofChebyshevLow Pass Filter with 0.01ripp le for order of N =3,4,5,6,7,8 and 9 and cut off frequency was set at 2.5GHz on substrate having dieletric 135903-7272-IJECS-IJENS © June 2013 IJENS IJ EN S

International Journal of Engineering & Computer Science IJECS-IJENS Vol:13 No:03 constant of 4.5 and thickness -1.5mm.One is the prototype usinglumped components, second is the microstrip without considering the fringing correction factorand thethird is considering the fringing correction factor . 3.1 ChebyshevLPF-0.01ripple, N =3, 4, 5, 6, 7, 8 and 9 simu lation result in ADS software fo r lu mped element circuit and microtsrip line filter are show as below,

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3.1.3 ChebyshevLPF-0.01ripple, N =5 the lumped element simulation result

Fig. 8 shows the simu lation result fo r Chebyshev, N=5 of lu mped element LPF with 0.01 ripple. The return loss, = 26.425dB and -3dB cutoff frequency falls at 3.228GHz.The matching of this circu it seemed good where the return loss is 3.1.1 ChebyshevLPF-0.01ripple, N =3 the lumped element below -20dB. However the designed cutoff frequency point is not simulation result at -3d B point but it falls at ripple, i.e-0.01d B of lo w pass filters. Fig. 6 shows the simulat ion result fo r Chebyshev, N=3 of The 2fc attenuation frequency is only -33.708d B. This means the lumped element LPF with 0.01 ripple. The return loss, = attenuation are enough to suppress the unwanted frequency -35.350d Band -3dB cutoff frequency falls at 4.691 GHz. The signal. matching of this circuit seemed good where the return loss is below -20d B. However the designed cutoff frequency point is m2 m1 m3 m4 freq= 2.500GHz freq=2.000GHz freq=3.228GHz freq= 6.000GHz not at -3dB point but it falls at ripple, i.e -0.01d B of low pass dB(S(1,1))=-26.425 dB(S(2,1))=-0.010 dB(S(2,1))=-3.010 dB(S(2,1))=-33.708 m2 m3 filters. The 2fc attenuation frequency is only -8.013d B. This m1 means the attenuation still not enough to suppress the unwanted m4 frequency signal. 0

dB(S(1,1)) dB(S(2,1))

-20

m1 freq=2.000GHz dB(S(1,1))=-35.350

m2 m3 freq=2.500GHz freq=4.691GHz dB(S(2,1))=-0.010 dB(S(2,1))=-3.001 m2 m3 m4

0

dB(S(1,1)) dB(S(2,1))

-20

-40 -60 -80

m4 freq=6.000GHz dB(S(2,1))=-8.013

-100 0

1

2

3

4

5

6

7

8

freq, GHz

m1

Fig. 8. simulation response of lumped lement circuit LPF at N-5 in ADS when fc=2.5GHz

-40 -60 -80

3.1.4 ChebyshevLPF-0.01ripple, N =6 the lumped element simulation result

-100 0

1

2

3

4

5

6

7

8

freq, GHz

Fig. 9 shows the simu lation result for Chebyshev, N=6 of lu mped element LPF with 0.01 ripple. The return loss, = 21.539 and -3dB cutoff frequency falls at 2.982GHz.The 3.1.2 ChebyshevLPF-0.01ripple, N =4 the lumped element matching of this circu it seemed good where the return loss is simulation result below -20dB. However the designed cutoff frequency point is not at -3d B point but it falls at ripple, i.e-0.01d B of lo w pass filters. Fig. 7 shows the simulat ion result for Chebyshev, N=4 of The 2fc attenuation frequency is seemed good where the lu mped element LPF with 0.01 ripple. The return loss, = - amp litude is fall below -40dB. This means the attenuation are 24.273dB and -3dB cutoff frequency falls at 3.623GHz.The good enough to suppress the unwanted frequency signal. matching of this circuit seemed good where the return loss is below -20d B. However the designed cutoff frequency point is m3 m1 m2 m4 freq= 2.982GHz freq=2.000GHz freq=2.500GHz freq= 6.000GHz not at -3dB point but it falls at ripple, i.e -0.01d B of low pass dB(S(1,1))=-21.539 dB(S(2,1))=-0.012 dB(S(2,1))=-3.014 dB(S(2,1))=-46.776 m2 filters. The 2fc attenuation frequency is only -20.433d B. This m3 means the attenuation are still considered not good enough to m1 suppress the unwanted frequency signal. Fig. 6. Simulation response of lumped lement circuit LPF at N-3 in ADS when fc=2.5GHz

0

dB(S(1,1)) dB(S(2,1))

-20

-60

m1 m2 m3 m4 freq=2.000GHz freq=2.353GHz freq=3.623GHz freq=6.000GHz dB(S(1,1))=-24.273 dB(S(2,1))=-0.012 dB(S(2,1))=-3.002 dB(S(2,1))=-20.433 m2

m4

-40

-80 0

1

2

3

4

5

6

7

8

freq, GHz

m3

0

dB(S(1,1)) dB(S(2,1))

-10

Fig. 9. Simulation response of lumped lement circuit LPF at N-6 in ADS when fc=2.5GHz

m4 m1

-20

-30

3.1.5 ChebyshevLPF-0.01ripple, N =7, the lumped element simulation result

-40 0

1

2

3

4

5

6

7

8

freq, GHz


Fig. 10 shows the simulat ion result for Chebyshev, N=7 of lu mped element LPF with 0.01 ripple. The return loss, = -


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39.950 and -3d B cutoff frequency falls at 2.863GHz. The amp litude is fall belo w -40dB. This means the attenuation are matching of this circuit seemed good where the return loss is good enough to suppress the unwanted frequency signal. below -20d B. However the designed cutoff frequency point is m3 m1 m2 m4 not at -3dB point but it falls at ripple, i.e -0.01d B of low pass freq=2.718GHz freq=2.000GHz freq=2.500GHz freq=6.000GHz dB(S(1,1))=-27.497 dB(S(2,1))=-0.010 dB(S(2,1))=-3.012 dB(S(2,1))=-86.588 filters. The 2fc attenuation frequency is seemed good where the m2 m3 amp litude is fall belo w -40d B. This means the attenuation are m1 good enough to suppress the unwanted frequency signal. 0

dB(S(1,1)) dB(S(2,1))

-20 -40 -60

m4

-80 -100 -120

m1 m2 m3 freq=2.000GHz freq=2.500GHz freq=2.863GHz dB(S(1,1))=-39.950 dB(S(2,1))=-0.010 dB(S(2,1))=-3.003

0

m4 freq=6.000GHz dB(S(2,1))=-60.150

1

2

3

4

5

6

7

8

freq, GHz

m2m3


0

dB(S(1,1)) dB(S(2,1))

-20

m1 -40

m4

3.2 Conversion to Microstrip line filters without taking fringing into consideration for Model π and T network when in ChebyshevLPF in microstrip line filter

-60 -80 -100 0

1

2

3

4

5

6

7

8

freq, GHz

3.2.1 Fig. 10. Simulation response of lumped lement circuit LPF at N-7 in ADS when fc=2.5GHz

3.1.6 ChebyshevLPF-0.01ripple, N =8 the lumped element simulation result Fig. 11 shows the simulation result for Chebyshev, N=8 of lu mped element LPF with 0.01 ripple. The return loss, = 15.346 and -3d B cutoff frequency falls at 2.892GHz. The matching of this circuit seemed not good where the return loss is above -20dB. However the designed cutoff frequency point is not at -3dB point but it falls at ripple, i.e -0.01d B of low pass filters. The 2fc attenuation frequency is seemed good where the amp litude is fall belo w -40d B. This means the attenuation are good enough to suppress the unwanted frequency signal.

ChebyshevLPF-0.01ripple, N =3 simulation result

Fig. 13 shows the simulat ion result for Chebyshev, N=3 of microstrip line filters with 0.01 ripple. The return loss, = 16.925dB and -3dB cutoff frequency falls at 3.645GHz. The matching of this circu it seemed not good enough where the return loss is above -20dB. Ho wever for microstrip line filters the designed cutoff frequency point is not at -3dB point but for ripple, i.e-0.01dB of low pass filters. The 2fc attenuation frequency is only -13.805d B @ 6.008GHz. This means the attenuation still not enough to suppress the unwanted frequency signal. m1 freq=2.063GHz dB(S_50(1,1))=-16.925

m2

0

m3 freq= 2.892GHz dB(S(2,1))=-3.025

dB(S_50(1,1)) dB(S_50(2,1))

m2 freq= 1.239GHz dB(S(2,1))=-0.012 m2 m3 m1

m4 freq= 6.000GHz dB(S(2,1))=-71.620

m4 freq=6.008GHz dB(S_50(2,1))=-13.805

m3

0

m4

m1

-10

m1 freq= 2.000GHz dB(S(1,1))=-15.346

m3 freq=3.645GHz dB(S_50(2,1))=-3.052

m2 freq=500.0MHz dB(S_50(2,1))=-0.020

-20 -30 -40 -50 -60 0

1

2

3

4

5

6

7

8

f req, GHz

dB(S(1,1)) dB(S(2,1))

-20 -40

Fig. 13. simulation response of microstrip line circuit after layout LPF at N-3 in ADS when fc=2.5GHz

m4

-60 -80 -100 0

1

2

3

4

5

6

7

8

freq, GHz


3.1.7 ChebyshevLPF-0.01ripple, N =9, the lumped element simulation result Fig. 12 shows the simulation result for Chebyshev, N=9 of lu mped element LPF with 0.01 ripple. The return loss, = 27.497 and -3d B cutoff frequency falls at 2.718GHz. The matching of this circuit seemed good where the return loss is below -20d B. However the designed cutoff frequency point is not at -3dB point but it falls at ripple, i.e -0.01d B of low pass filters. The 2fc attenuation frequency is seemed good where the

3.2.2 ChebyshevLPF-0.01ripple, N =4 simulation result Fig. 14 shows the simulat ion result for Chebyshev, N=4 of microstrip line filters with 0.01 ripple. The return loss, = 7.991d B and -3dB cutoff frequency falls at 3.039GHz. The matching of this circu it seemed not good enough where the return loss is above -20dB. Ho wever for microstrip line filters the designed cutoff frequency point is not at -3dB point but for ripple, i.e-0.01dB of low pass filters. The 2fc attenuation frequency is only -35.589dB. Th is means the attenuation still consider enough to suppress the unwanted frequency signal.


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3.2.5 ChebyshevLPF-0.01ripple, N =7 simulation result Fig. 17 shows the simulat ion result for Chebyshev, N=7 of microstrip line filters with 0.01 ripple. The return loss, = 4.751d B and -3dB cutoff frequency falls at 2.047GHz. The matching of this circu it seemed not good enough where the return loss is above -20dB. Ho wever for microstrip line filters the designed cutoff frequency point is not at -3dB point but for ripple, i.e-0.01dB of low pass filters. The 2fc attenuation Fig. 14 simulation response of microstrip line circuit after layout LPF at N-4 in frequency is only -39.444dB. Th is means the attenuation still ADS when fc=2.5GHz consider enough to suppress the unwanted frequency signal. m1 freq= 2.004GHz dB(S_50(1,1))=-7.991

m2 freq= 500.0MHz dB(S_50(2,1))=-0.099 m2

dB(S_50(1,1)) dB(S_50(2,1))

m3

m1

0

m4 freq= 6.008GHz dB(S_50(2,1))=-35.589

m3 freq= 3.039GHz dB(S_50(2,1))=-3.157

-20

m4

-40

-60

-80

0

1

2

3

4

5

6

7

8

f req, GHz


Fig. 15 shows the simulation result for Chebyshev, N=5 of microstrip line filters with 0.01 ripp le. The return loss, = 10.976dB and -3dB cutoff frequency falls at 2.414GHz. The matching of this circu it seemed not good enough where the return loss is above -20dB. However fo r microstrip line filters the designed cutoff frequency point is not at -3dB point but for ripple, i.e-0.01dB of low pass filters . The 2fc attenuation frequency is only -33.489dB. Th is means the attenuation still consider enough to suppress the unwanted frequency signal. m1 freq= 2.002GHz dB(S_50(1,1))=-10.976

m3 freq= 2.414GHz dB(S_50(2,1))=-3.141

m2 freq= 500.0MHz dB(S_50(2,1))=-0.045 m2

m2 freq= 500.0MHz dB(S_50(2,1))=-0.079 m2 m3 0 m1

m3 freq= 2.047GHz dB(S_50(2,1))=-3.010

m4 freq= 6.031GHz dB(S_50(2,1))=-39.444

-10 -20 -30

m4

-40 -50 0

1

2

3

4

5

6

7

8

f req, GHz


3.2.6


m3

0

dB(S_50(1,1)) dB(S_50(2,1))

m4 freq= 6.008GHz dB(S_50(2,1))=-33.489

m1 freq= 2.000GHz dB(S_50(1,1))=-4.751

dB(S_50(1,1)) dB(S_50(2,1))

3.2.3

m1 -10

Fig. 18 shows the simulat ion result for Chebyshev, N=8 of microstrip line filters with 0.01 ripple. The return loss, = 3.153d B and -3dB cutoff frequency falls at 2.010GHz. The matching of this circu it seemed not good enough where the return loss is above -20dB. Ho wever for microstrip line filters the Fig. 15 simulation response of microstrip line circuit after layout LPF at N-5 in designed cutoff frequency point is not at -3dB point but for ADS when fc=2.5GHz ripple, i.e-0.01dB of low pass filters. The 2fc attenuation frequency is seemed good where the amp litude is fall belo w 3.2.4 ChebyshevLPF-0.01ripple, N =6 simulation result 40d B. This means the attenuation are good enough to suppress the unwanted frequency signal. Fig. 16 shows the simulation result for Chebyshev, N=6 of microstrip line filters with 0.01 ripp le. The return loss, = 2.319d B and -3dB cutoff frequency falls at 2.245GHz. The m1 m2 m3 m4 freq=2.010GHz freq=500.0MHz matching of this circu it seemed not good enough where the freq=2.010GHz freq=6.008GHz dB(S_50(2,1))=-3.153 dB(S_50(2,1))=-0.135 dB(S_50(2,1))=-3.153 dB(S_50(2,1))=-48.678 m2 return loss is above -20dB. However fo r microstrip line filters m1 m3 the designed cutoff frequency point is not at -3dB point but for ripple, i.e-0.01dB of low pass filters. The 2fc attenuation frequency is seemed good where the amplitude is fall belo w m4 40d B. This means the attenuation are good enough to suppress the unwanted frequency signal. -20

m4

-30

-40

0

1

2

3

4

5

6

7

8

f req, GHz

0

dB(S_50(1,1)) dB(S_50(2,1))

-10 -20 -30 -40 -50 -60

0

1

2

3

4

5

6

7

8

f req, GHz

m2 freq= 500.0MHz dB(S_50(2,1))=-0.142 m2 m1 m3 0 dB(S_50(1,1)) dB(S_50(2,1))

m1 freq= 2.004GHz dB(S_50(2,1))=-2.319

m3 freq= 2.245GHz dB(S_50(2,1))=-3.017

m4 freq= 6.008GHz dB(S_50(2,1))=-46.574

-10


3.2.7

-20


-30 -40

m4

-50 0

1

2

3

4

freq, GHz

5

6

7

8

Fig. 19 shows the simulat ion result for Chebyshev, N=9 of microstrip line filters with 0.01 ripple. The return loss, = 1.029d B and -3dB cutoff frequency falls at 1.888GHz. The matching of this circu it seemed not good enough where the return loss is above -20dB. Ho wever for microstrip line filters the 135903-7272-IJECS-IJENS © June 2013 IJENS

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m1 freq=2.009GHz dB(S_50(1,1))=-1.029

m3 freq=1.888GHz dB(S_50(2,1))=-3.047

m2 freq=500.0MHz dB(S_50(2,1))=-0.114 m2 m1 m3

m1 m2 freq=2.023GHz freq=500.0MHz dB(S_50(1,1))=-7.866 dB(S_50(2,1))=-0.106 m2 0

dB(S_50(1,1)) dB(S_50(2,1))

designed cutoff frequency point is not at -3dB point but for ripple, i.e-0.01dB of low pass filters. The 2fc attenuation frequency is seemed good where the amplitude is fall belo w 40d B. This means the attenuation are good enough to suppress the unwanted frequency signal.

m1

27

m3 m4 freq=3.272GHz freq=6.021GHz dB(S_50(2,1))=-3.037 dB(S_50(2,1))=-33.941

m3

-10 -20

m4

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m4 freq=6.025GHz dB(S_50(2,1))=-40.207

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3.3.3 ChebyshevLPF-0.01ripple, N =5 simulation result Fig. 22 shows the simulat ion result for Chebyshev, N=5 of microstrip line filters with 0.01 ripple. The return loss, = Fig. 19. simulation response of microstrip line circuit after layout LPF at N-9 in 17.922dB and -3dB cutoff frequency falls at 2.688GHz. The ADS when fc=2.5GHz matching of this circu it seemed not good enough where the return 3.3 Conversion to Microstripline filters with taking loss is above -20dB. Ho wever for microstrip line filters the fringing into consideration for Model  and T network when in designed cutoff frequency point is not at -3dB point but for ripple, i.e-0.01dB of low pass filters. The 2fc attenuation ChebyshevLPF in microstrip line filter frequency is only -32.124dB. Th is means the attenuation still consider enough to suppress the unwanted frequency signal. 3.3.1 ChebyshevLPF-0.01ripple, N =3 simulation result Fig. 20 shows the simulation result for Chebyshev, N=3 of microstrip line filters with 0.01 ripp le. The return loss, = m1 m3 m2 m4 freq=2.004GHz freq=2.688GHz freq=500.0MHz freq=6.008GHz dB(S_50(1,1))=-17.922 dB(S_50(2,1))=-0.044 dB(S_50(2,1))=-3.096 dB(S_50(2,1))=-32.124 20.013dB and -3dB cutoff frequency falls at 3.859GHz.The m2 m3 matching of this circuit seemed good where the return loss is below -20d B. However for microstrip line filters the designed m1 cutoff frequency point is not at -3dB point but for ripple, i.em4 0.01d B of lo w pass filters. The 2fc attenuation frequency is only -12.727d B. Th is means the attenuation still not en ough to suppress the unwanted frequency signal. f req, GHz

dB(S_50(1,1)) dB(S_50(2,1))

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f req, GHz

m2 freq=500.0MHz dB(S_50(2,1))=-0.018

m1 freq=2.004GHz dB(S_50(1,1))=-20.013

m2

m3 freq=3.859GHz dB(S_50(2,1))=-3.017

m4 freq=6.008GHz dB(S_50(2,1))=-12.727


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m1 f req=2.007GHz dB(S_50(1,1))=-6.402

m2 f req=500.0MHz dB(S_50(2,1))=-0.156 m2

0

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m3 f req=2.725GHz dB(S_50(2,1))=-3.063

m4 f req=6.008GHz dB(S_50(2,1))=-44.569

m3

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dB(S_50(1,1)) dB(S_50(2,1))

dB(S_50(1,1)) dB(S_50(2,1))

3.3.4 ChebyshevLPF-0.01ripple, N =6 simulation result Fig. 23 shows the simulation result for Chebyshev, N=6 of microstrip line filters with 0.01 ripple. The return loss, = 6.402d B and -3dB cutoff frequency falls at 2.725GHz. The matching of this circu it seemed not good enough where the return loss is above -20dB. Ho wever for microstrip line filters the designed cutoff frequency point is not at -3dB point but for Fig. 20. simulation response of microstrip line circuit after layout LPF at N-3 in ripple, i.e-0.01dB of low pass filters. The 2fc attenuation ADS when fc=2.5GHz frequency is seemed good where the amp litude is fall belo w 40d B. This means the attenuation are good enough to suppress 3.3.2 ChebyshevLPF-0.01ripple, N =4 simulation result Fig. 21 shows the simu lation result for Chebyshev, N=4 of the unwanted frequency signal. microstrip line filters with 0.01 ripp le. The return loss, = 7.861d B and -3dB cutoff frequency falls at 3.272GHz. The matching of this circu it seemed not good enough where the return loss is above -20dB. However fo r microstrip line filters the designed cutoff frequency point is not at -3dB point but for ripple, i.e-0.01dB of low pass filters. The 2fc attenuation frequency is only -33.941dB. Th is means the attenuation still consider enough to suppress the unwanted frequency signal. m4

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3.3.5 ChebyshevLPF-0.01ripple, N =7 simulation result m1 m2 m3 m4 freq= 2.002GHz freq= 500.0MHz freq= 2.262GHz freq= 6.008GHz Fig. 24 shows the simulation result for Chebyshev, N=7 of dB(S_50(1,1))=-24.235 dB(S_50(2,1))=-0.121 dB(S_50(2,1))=-3.051 dB(S_50(2,1))=-43.595 m2 m3 microstrip line filters with 0.01 ripp le. The return loss, = 24.804dB and -3dB cutoff frequency falls at 2.375GHz.The m1 matching of this circuit seemed good where the return loss is m4 below -20d B. However for microstrip line filters the designed cutoff frequency point is not at -3dB point but for ripple, i.e0.01d B of lo w pass filters. The 2fc attenuation frequency is only -39.411d B. Th is means the attenuation are consider enough to suppress the unwanted frequency signal. Fig. 26. simulation response of microstrip line circuit after layout LPF at N-9 in 0

dB(S_50(1,1)) dB(S_50(2,1))

-10 -20 -30 -40 -50 -60

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f req, GHz

ADS when fc=2.5GHz m2 freq=500.0MHz dB(S_50(2,1))=-0.081 m2 m3 0

m1 freq=2.004GHz dB(S_50(1,1))=-24.804

m3 freq=2.375GHz dB(S_50(2,1))=-3.067

m4 freq=6.008GHz dB(S_50(2,1))=-39.411

dB(S_50(1,1)) dB(S_50(2,1))

-10

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m4 -40 -50 0

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f req, GHz


3.3.6 ChebyshevLPF-0.01ripple, N =8 simulation result Fig. 25 shows the simulation result for Chebyshev, N=8 of microstrip line filters with 0.01 ripp le. The return loss, = 16.638dB and -3dB cutoff frequency falls at 2.328GHz. The matching of this circu it seemed not good enough where the return loss is above -20dB. However fo r microstrip line filters the designed cutoff frequency point is not at -3dB point but for ripple, i.e-0.01dB of low pass filters. The 2fc attenuation frequency is seemed good where the amplitude is fall belo w 40d B. This means the attenuation are good enough to suppress the unwanted frequency signal. m1 freq= 2.000GHz dB(S_50(1,1))=-16.638

m3 freq= 2.328GHz dB(S_50(2,1))=-3.096

dB(S_50(1,1)) dB(S_50(2,1))

m2 freq= 500.0MHz dB(S_50(2,1))=-0.140 m2 m3 0

m4 freq= 6.031GHz dB(S_50(2,1))=-48.248

m1

-10 -20 -30 -40

m4

-50 -60 0

1

2

3

4

5

6

7

8

f req, GHz


3.3.7 ChebyshevLPF-0.01ripple, N =9 simulation result Fig. 26 shows the simulation result for Chebyshev, N=9 of microstrip line filters with 0.01 ripp le. The return loss, = 24.235dB and -3dB cutoff frequency falls at 2.262GHz. The matching o f this circuit seemed good enough where the return loss is below -20dB. However for microstrip line filters the designed cutoff frequency point is not at -3dB point but for ripple, i.e-0.01dB of low pass filters. The 2fc attenuation frequency is seemed good where the amplitude is fall belo w 40d B. This means the attenuation are good enough to suppress the unwanted frequency signal.

IV. RESULT A ND A NALYSIS Fro m the plot, the S-parameter simulat ion results of lumped element circu it and microstrip line simulat ion result with fringing correction agree well with each other in ADS simu lation. The simulation result of lu mped element N=3,4,5,6,7,8 and 9 show that cut off frequency response fc2.5GHz is seemed at the ripple value of 0.01dB. Fro m the microstrip filter circuit simu lation result without taking fringing into consideration, the results show that when the N increased the respond of return loss S 11 become wo rse because the matching of this circuit seemed not good enough where the return loss amplitude is above -20d B but the S21 where amplitude is fall below -40dB are getting improved. Fro m the microstrip filter circu it simulat ion result with taking fringing into consideration, the graphs show that there turn loss S11 and S21 when N increased the result are imp roved and frequency response is approximately to ideal filter design frequency, but the ripple value of 0.01d B seemed located at frequency response less than 2.5GHz. The frequency response of return loss keep on approaches on the required design specification as the order N is increased. The analytical result of lu mped element circuit co mpared with new approach of transforming lu mped element circu it into microstrip line, the simu lation results show that the new approach achieved excellent agreement with the designed. V. SCOPES & LIMIT AT IONS The main scope and limitations of this project is to design and development a new approach of t ransforming lu mped elements circuit into microstrip line for all high-order Chebyshev low pass filter wh ich operating within UHF range. The filters were designed, simulated and imp lemented on FR4 substrate using Advanced Design Software (ADS) for both lu mped element and microstrip filters. Correction factor has been considered due to fringing inductor and capacitor. The A DS simulat ion results show that the response of microstrip line circuit of Chebyshev low pass filter with fring ing correction factor has an excellent agreement with its lu mped circuit. Even the designed cutoff frequency of value 2.5GHz for lu mped element circuit does not fall on the -3dB but it falls on the ripple value of normalized Chebyshev. However the microstrip filter output performance with the new approach almost closed to 2.5GHz co mpare to lumped element. VI. CONCLUSION Overall, simu lation result show that, the filter with


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International Journal of Engineering & Computer Science IJECS-IJENS Vol:13 No:03 fringing taking into consideration is closed to the designed prototype compared to the result of the filter without taking fringing into consideration. The designed cutoff frequency of value 2.5GHz for lu mped element circu it does not fall on the 3dB but it falls on the ripple value of normalized Chebyshev. However the microstrip filter with the new approach almost closed to 2.5GHz. Further works will be fabricat ing the filters into MEM S technology. A new approach method not only limited to apply on Chebyshev filter, but also elig ible to apply on other type of low pass filter such as butterworth, composite or elliptic low pass filter. VII. A CKNOWLEDGEMENT S The authors would like to acknowledge University Malaysia Perlis and the Malaysian Ministry of Higher Education for provid ing the Fundamental Research Grant Scheme (FRGS Grant No : 9011-00011) wh ich enabled to publication of this article.

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Systems,” IEEE Symposium on Wireless Technology and Applications ,September, 2012, pp. 75-80. V.Crnojevic-Bengin and D.Budimir, “Design of Thick Film Microstrip Low Pass Filters,” International Conference on Telecommunications in Modern Satellite, Cable and Broadcasting Services, TELSIKS 2003, pp360-362. G. L. Matthaei, “Tables of chebyshev impedance transforming networks of low-pass filters form,” Proc IEEE. vol. 52, no. 8, pp. 939963, March, 1964. L. Young, “Microwave filters-1965,” IEEE Trans. Microwave Theory and Techniques, vol. 13, pp. 489 508, September, 1965. Hisham L. Swady, “ Generalized Chebyshev-like Approximation for Low-Pass Filter, ”20101stInternational Conference on Energy, Power andControl(EPCI Q),CollegeofEngineering,UniversityofBasrah,Basrah, Iraq, November 30 –December2, 2010. N. T. Hoang, H.D. T uan, T. Q. Nguyen, and H. G. Hoang," Optimized Analog Filter Designs With Flat responses by Semi Definite Programming", IEEE Trans. Signal Processing, Vol. 57, No. 3, March 2009. JiashenG.Hong ,M.J.Lancaster, “ Microstrip Filters for RF/ Microwave Applications,” John Wiley & Son Inc, 2001. D. Swanson and G. Macchiarella, “Microwave filter design by synthesis and optimization,” IEEE Microwaves Mag, vol. 8, no. 2, pp.55-69, Apr. 2007. Inc., N.Y.,2001. R. Levy, R. V. Snyder, and G. Matthaei, “Design of microwave filters,” IEEE Trans. Microw. Theory Tech., vol. 50, PP. 783 793,March 2002. T ilmans H. A C,Raedt W. D. &Beyne E. (2003), “MEMS for wireless communications: „from RF MEMS components to RF-MEMS-SIP”, J. Micromech. Microeng,pp. 139-163, vol. 13,2003. S.C.DuttaRoy, "A New Chebyshev- like Low- pass Filt er Approximation" ,Springer Science Business Media, LLC2010,CircuitSyst.Signalprocess,Vol.29, pp629-636. YanlingHao, BingfaZu and Ping Huang, “An Optimal Microtsrip Filter Design Method Based On Advanced Design System for Satellite Received,” Proceedings of International Conference on Mechatronics and Automation.2008.

Liew Hui Fang was born in Penang, Malaysia in 1988.She received bachelor's degree in Electrical System Engineering from University Malaysia Perlis (UniMAP), Malaysia, in 2012. She is persuing her Master of Microelectronics Engineering and she currently continues study in UniMAP. Her area of research is in Microwave Communication /RF MEMS. Syed Idris Syed Hassan graduated in physics from National University of Malaysia in 1979. He persuing his Master in Radar and radio communication from University of Birmingham in 1980. He obtained his PhD in Antennas and propagation from University of Exeter 1n 1987.Currently he is a Professor at School of Electrical System Envgineering. His research interest includes Antenna, RF propagation, Microwave Engineering, Radar, Satellite, EMC and power quality. He is currently a lecturer at School of Electrical System Engineering, University Malaysia Perlis (UniMAP) Mohd Fareq Bin Abd. Malek (M‟11) received his B.Eng. (Hons.) degree from The University of Birmingham, U. K. in 1997 and the M.Sc. (Eng.) (Distinction) and Ph.D. degrees from The University of Liverpool, U. K. in 2004 and 2008, respectively. From 2008 to 2011, he was a Deputy Dean (Academic and Research) in the School of Computer and Communication Engineering at Universiti Malaysia Perlis (UniMAP). Since 2011, he has been the Dean of the School of Electrical System Engineering at Universiti Malaysia Perlis (UniMAP), where he lectures in the areas of electromagnetic and communication system. Current research activities include small antennas, dielectric resonator, array antennas and bioelectromagnetics. Previous employment includes Alcatel Network Systems (Malaysia) Sdn Bhd and Siemens (Malaysia) Sdn Bhd, where he served in the mobile networks division and the information, communication and mobile group, respectively. He was a recipient of the International Students Scholarship from the Department of Electrical Engineering and Electronics, The University of Liverpool, U. K., Outstanding Member award for the School of Computer and Communication Engineering, UniMAP (2010), and the CST University Publication Award (2011). Since 2010, he has been a fellow at International Telecommunication Union – Universiti Utara Malaysia (IT U-UUM) Center of Excellence for rural ICT. He is currently a lecturer at School of Electrical System Engineering, University Malaysia Perlis (UniMAP).


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Yufridin Bin Wahab received his Bachelor of Engineering (hons.) in Electrical and Electronic Engineering from University Sains Malaysia (USM) in 1996. He worked as Research Officer in the same university and fabricated his research using MOSIS service to complete his MSc in VLSI Design in 1999 in the same faculty. In 1999, he started his job as one of the first few engineers in Malaysia's first commercial semiconductor wafer foundry, named Silterra Malaysia Sdn Bhd. His one year experience working in LSI Logic Corporation in the Gresham, USA equipped him with real international industrial experience in semiconductor fabricat ion. He then joined USM as a lecturer. In early 2002, he co-developed the curriculum for the Bachelor of Engineering in Microelectronic Engineering degree programme for the newly opened Kolej Universiti Kejuruteraan Utara Malaysia (KUKUM) and joined university in May that year and helped to set-up the School of Microelectronic Engineering in just one month before the first student intake in June 2002. He also founded the Centre for Industrial Collaboration for the university in 2003 and sent the university‟s first engineering trainees to the industry throughout Malaysia. He completed his PhD at Victoria University, Melbourne, Australia specializing in Micro -ElectroMechanical System design, fabrication and testing using Infineon T echnology‟s MPW service in 2009. In 2011, under his leadership, his team was awarded RM 2.27 million grant for MEMS development from industries. He is currently a lecturer at School of Microelectronic Engineering, University Malaysia Perlis (UniMAP). Norshafinash Binti Saudin received her B. Eng. (Hons) in Electrical and M. Eng in Electrical (Power) from University Technology Malaysia in 2005 and 2007 respectively. Her research interest includes power system stability, power quality, and power electronics. She is currently a lecturer at School of Electrical System Engineering, University Malaysia Perlis (UniMAP).


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