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Procedia Engineering
ProcediaProcedia Engineering 00 (2012) 000–000 Engineering 32 (2012) 531 – 535 www.elsevier.com/locate/procedia
I-SEEC2011
A novel design of the Bandpass Filter Open-Loop with an Inductive Compensated Coupled Line M. Jamsaia, N. Thammawongsab, N. Pornsuwancharoena, R. Phromloungsrib a
Department of Electrical Engineering, Faculty of Indusltry and Technology Rajamangala University of Technology lean, Sakonnakon 47160, Thailand. b Department of Electrical Engineering, Udon Thani Rajabhat University 64 Udon Thani Rajabhat University, Muang, Udon Thani 41000, Thailand Elsevier use only: Received 30 September 2011; Revised 10 November 2011; Accepted 25 November 2011.
Abstract This article presents techniques for the design of bandpass filter open-loop which is able to push the frequency 2f0 and 3f0. The circuit structure consists of a grid connected to a parallel-coupled line one-eighth wavelength long served as resonator connected the router to a variable electric field and the frequency response in artificial implant is placed in the center of the circuit. With the transmission line, a step at the input port and output as matching circuit when comparing the results of simulation and measurement results of the circuit at a frequency of 0.9 GHz. The result found that the presented circuit is able to reduce the frequency response of a false pseudo 1.8 and 2.7 GHz. for more than 30 and 19 decibels respectively.
© 2010 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of I-SEEC2011 Keywords: parallel-coupled lines; Open-loop bandpass filter; Compensated inductor
1. Introduction Nowadays, the wireless communication system has developed and progressed rapidly. That is because researchers around the world dedicated to design and do research to improve various aspects of devices and circuits for wireless communication systems seriously. One of the major components of the system is filter through a microwave frequency which is responsible for filtering the harmonic
* Corresponding author. E-mail address:
[email protected].
1877-7058 © 2012 Published by Elsevier Ltd. doi:10.1016/j.proeng.2012.01.1304
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(a) (b) Fig. 1. Presented open-loop bandpass filter (a) normal and (b) connecting the inductor to reduce the size of the harmonics signal
In general, the design of the filter through the researchers tends to focus on improving the frequency response around. Passband and transition band to the size of the attenuation (roll-off factor) in the frequency range and size of the frequency response in the frequency range of transition to a dramatically reduced. This will result in a cycle that is created to reduce the size of a false pseudo-frequency response and harmonic frequencies which is away from the frequency response of the circuit. In addition, the tuning range of a loss of interference and loss of the low back [1] It is one thing that must be considered. In the design of the filter through microwave frequencies, the design uses a parallel cable to connect it which is required the parallel port of the transmission line connected to two ports, the input port and output ports, two USB ports. The remaining two ports may be open circuit or short circuit ground. But in the design of the transmission line connected to the parallel structure of the circuit is likely to impact the frequency response of a false pseudo-mixed into the frequency response [2-5]. Research on the structure, the transmission lines are connected in parallel with an induction that is designed specifically for microwave frequency communications such as Marchan balance circuit and resonator circuit [6-8], This article, the researchers were interested in the transmission line to connect the parallel connected inductors. Used in the design of the filter through which an open loop structure in Figure 1 with the aim that the research developed in this can be used in various wireless communication systems in radio and microwave frequency 2. Open-loop bandpass filter resonator circuit Bandpass filter may be synthesized from micro-strip transmission line or micro-strip [7], filter strips coupled line. The most well-known filter is a filter which the transmission line connected to the parallel synthesis of many stage (n-stages) because of it can be easily designed and constructed. There's a problem of artificial frequency response and harmonic, especially in higher frequency harmonics 2f 0the frequency responses in the asymmetric bars. In the past, it has presented the design of the filter through a closed loop structure with dual-mode behavior. The form of the electromagnetic energy in the opening around of the magnetic and electric fields resulted in the research involved in designing and developing an open-loop resonator circuit [8]. These studies tend to focus on improving the
Fig. 2. Open-loop bandpass filter resonator circuit
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quality of the work of a particular type of frequency response and the ability to forge an artificial signal. In this paper, a principle similar to the previous method [7], but differ in the structure of the resistance which is the frequency of the circuit structure shown in Figure2. In this study, the combination of transmission lines connected in parallel with the inductor in the circuit to improve the frequency response of the circuit for the better. By the induction will allow us to direct equity line connected in parallel with a high rate and a near zero-frequency operation as in the following equation. Ln
=
ì-Z (Z 2 + Z 2 ) sinh q + Z (Z 2 + Z 2 ) sinh q - 2Z 3Á ïü ï 1 o e 0 0o 0e 0 0 ï ï 0e 0o Im í ý ï 2p f0 Z 0 (Z 0e sinh qo + Z 0o sinh qe ) - Z 02Á ï ïïþï ï î
(1)
Where Á = cosh qe - cosh qo , e / 2 the angular length of the cable is connected in parallel for dualmode waves and qo = (p 2) Q is the length of the cable parallel to the angular frequency in odd modes
and effo effe respectively. In the circuit design of parallel transmission lines connected to the conventional and transmission line connected to the parallel-connected inductors are connected in parallel to the line of slightly less than 5 percent of the original structure. 3. Design and Experimental results The research was designed open-loop bandpass filter at the frequency of 0.9 GHz. on the circuit boards FR60 ( er = 4.6, h =1.6 mm, tand=0.02 ). The normal and transmission lines are connected in parallel to the inductor as in Figure 1 a) and 1 b), respectively, whereas the constant for the Electric relative to the wave mode with mode and odd as = 4.667, = 3.567 and physical dimensions are as follows: W = 1.82 mm., S = 0.3 mm. and L = 15.4 mm. from the variable power are used to calculate the inductor compensation and length of angular contraction shortened by equation (1) and (2) is equal to 0.93 Nan Henry and 0.43 , respectively, connected to the inductor in the circuit. It is necessary to reduce the length of the transmission lines connected in parallel from q = 0.5p changed into qQ = 0.43p so the width of the gap of transmission lines connected to parallel (S) must be reduced from 0.30 mm to 0.25 mm. in order to maintain the connection coefficient is equal to the original value.
Fig. 3. simulates the operation of unconnected open-loop bandpass filter (thin line) and connected to 4 inductors (thick lines)
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M. Jamsai / Procedia Engineering 32 (2012) 531 – 535 M. Jamsai et al.et/ al. Procedia Engineering 00 (2012) 000–000
Fig. 4. Shows the measurement results of unconnected open-loop bandpass filter (thin line) and connected to four inductors (thick lines)
Ou tp ut
Inp u t Feed Lin e
Feed Lin e
Outp ut
I np ut
Feed Lin e
Feed Line
Ln
Ln
(a) (b) Fig. 5. Open-loop bandpass circuit board (a) connected and (b) unconnected to four inductors
Variations of the transmission line connecting both normal and parallel to the inductor is shown in Table 1. The simulation of the transmission line connected to the parallel normal and connected to the inductor shown in Figure 3 is a circuit that delivers a loss of interference S21 and the loss of backward S11 at a frequency of 900 MHz is about -0.23 and less than -18 dB, while the ability of the frequency response at the frequency 2f0 fake, artificial, or at a frequency 1.8 GHz is about 30 decibels in the measurement experiments. In this study, the electrical network analyzer (E5062A Network Analyzer) that is calibrated from 0.1 to 3.0 GHz using HPVEE6.0TM program. Table 1. Parameters Techniques Cpl # 1 Cpl #2 L1
Z0 () 50 50 50
W,S,L (mm) 2.4, 0.20, 26.0 2.4, 0.20, 21.0 W= 2.4, L=21
The results of the GPIB card using Matlab to analyze and display the results, the performance of the circuit shown in Figure 4, the loss of interference and reverse the loss of the frequency f0 of the circuit is equal to -0.32 and -18 dB, while the frequency response at a frequency of 1.8 GHz prosthetic makeup is about 29.2 dB close to the results of the simulation. Circuit board used in the experiment, both normal and connected to four inductors shown in Figure 5 a) and 5 b) of the experimental results presented to the circuit, connect the cassette case as in many stage, it will filter through the open ring with the ability to forge an artificial signal in the frequency range for the better, it is possible to apply vastly
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4. Conclusion Open-loop bandpass filter 0.9 GHz. that has been built and able connect to the parallel-coupled lines inductive compensation. It is able to respond to about 20 decibels at a harmonic frequency. Design for active, it can be done by using a simple equation and made it easy to use. It is suitable to be applied to wireless communications and microwave communications systems as well. Acknowledgments The authors would like to thank Faculty of Industry and Technology, Rajamangala University of Technology Isan, Sakon Nakhon Campus and Udon Thani Rajabhat University for fund supporting. References [1] T. Edward, Foundation for Microstrip Circuit Design, West Sussex, England: John Wiley & Son, 1992. [2] R. Phromloungsri, Chongcheawchamnan, and I. D. Robertson, “Inductively compensated parallel-coupled microstrip lines and their applications”, IEEE Trans. Microwave Theory Tech., vol. 54, no.9, pp. 3571-3582, Sept. 2006. [3] M. Dydyk, “Microstrip directional couplers with ideal performance via single-element compensation”, IEEE Trans. Microwave Theory Tech., vol. 47, no.6,pp. 969-976, June 1989. [4] S. F. Chang, J. J. Chen, Y. H. Jeng and C. T. Wu, “New high-directivity coupler design with coupled spurlines”, IEEE Microwave and Wireless Components Lett., vol. 14, no.2, pp.65-67, Feb. 2004. [5] R. Phromloungsri, V. Chamnanphrai, and M. Chongcheawchamnan, “Quadruply-Inductive Compensated Parallel-Coupled Lines”, in 2006 Asia Pacific Microwave Con., Dec. 2006, pp. 2840-2843. [6] S. Uysal and H. Aghvami, “Synthesis, design, and construction of ultra- wide-band nonuniform quadrature directional couplers in inhomogeneous media ”, IEEE Trans. Microwave Theory Tech., vol. 37, no.6, pp. 969-976, June 1989. [7] G. L. Matthaei, L. Yolig, and E.M.T Jones, Microwave Impedance- Matching Network and Coupling Structures, New York: McGraw-Hill, pp.583-593,1964. [8] J. S. Hong, and M. J. Langcaster, “Theory and experiment of novel microstrip slow-wave open-loop resonator filter”, in 2006 IEEE Trans. Microwave Theory Tech., vol. 45, no.12, pp. 2358-2365, Dec. 2006.
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