12th International Conference on Microwaves, Antenna, Propagation & Remote Sensing ICMARS-2017, Jodhpur, INDIA, Feb. 15 – 17, 2017
Substrate Integrated Waveguide fed Circularly Polarized Cylindrical Dielectric Resonator Antenna Rudraishwarya Banerjee#1, Biswarup Rana#2, Susanta Kumar Parui#3 #
Department of Electronics and Telecommunication Engineering, Indian Institute of Engineering Science and Technology, Shibpur Howrah, West Bengal, India 1
[email protected] 2
[email protected] 3
[email protected]
Abstract—Here, a substrate integrated waveguide (SIW) is used to feed a cylindrical dielectric resonator antenna (CDRA), and an offset non radiating cross slot is intuitively designed to excite circular polarization (CP) in the CDRA. This work proffers a new simple feeding mechanism to obtain CP in CDRA, especially at high frequencies. The proposed antenna offers 2% axial ratio bandwidth around 14.1 GHz, with 6 dBi CP gain at 14.1 GHz.
(a)
Keywords— Dielectric resonator antenna (DRA), substrate integrated waveguide (SIW), gain, circularly polarized.
I. INTRODUCTION Recently, substrate integrated waveguide (SIW) technology, which is also known as post wall waveguide technology, has attracted significant attention in high frequency works, due to its various advantageous properties, like, low radiation loss, high quality-factor and high powerhandling capability and so forth [1]. On the other hand, dielectric resonator antenna (DRA) has already became much popular for its different attractive properties, most mention worthy of which is the fact that various feeding mechanisms can be used to excite the DRA [2-6]. Here, the emerging SIW technology is used to feed a simple cylindrical DRA, and an offset cross-slot is designed to achieve circular polarization (CP) in DRA. Eventually, nowadays, CP antenna has got a lot of importance in several communication systems. In [7], a SIW fed DRA array was reported which was a linear polarized antenna array. A CDRA placed on a cross-slot fed with a microstrip line, which excites CP around 2.04 GHz, has already been explored [6]. But, the major disadvantage of that work is the generation of high back lobe due to unwanted radiation from the slot. Moreover, microstrip line itself begins to radiate at high frequencies, and also suffers from conductor loss, which make that technique misfit for high frequency applications. Here, these problems are resolved. So, this work proffers a simple mechanism to achieve CP in DRA, especially for high frequency applications.
r l W
l
H
w (b)
(c)
(d)
(e) Fig. 1 (a) Substrate integrated waveguide (b) Configuration of the cross slots (c) The CDRA (d) SIW fed cross-slots (e) Top view of the antenna (when CDRA is placed over the cross-slots).
175
12th International Conference on Microwaves, Antenna, Propagation & Remote Sensing ICMARS-2017, Jodhpur, INDIA, Feb. 15 – 17, 2017
II. ANTENNA CONFIGURATION Fig. 1(a) shows the substrate integrated waveguide, where L=30 mm, and W=10 mm. Then Fig. 1(b) shows the geometry of the cross-slot, where w = 1 mm and l = 5 mm. Fig. 1(c) indicates the dimension of the cylindrical DRA (CDRA) used, where r = 3 mm, and H=8 mm. In Figure 1(d), the SIW fed offset cross-slots are shown, where dx=1.5 mm and dm=1mm, which indicates that the vertical slot is 1.5 mm offset and the horizontal slot is 1mm offset along the X-axis from the middle of the SIW structure. Fig. 1(e) gives the top view of the antenna, when the CDRA is placed over the cross-slot. Here, the dielectric constant of the CDRA used is ε r = 10, and that of the substrate is ε s =3.2. The thickness of the substrate is 0.79 mm.
0
S11 (dB) Axial Ratio (dB)
-5
8 7 6
-10
4
S11(dB)
-15
3
-20
2 -25
Axial Ratio (dB)
5
1
-30 13.0
13.5
14.0
0 15.0
14.5
frequency(GHz)
III. SIMULATED RESULTS Fig. 2 shows the return loss characteristics of the SIW structure, where, it is seen that the cut off frequency of the waveguide is nearly 12 GHz. Fig. 3 shows the return loss and the axial ratio (AR) along the broadside of the proposed antenna configuration, where it is observed that the S 11 < -10 dB along with AR < 3 dB over a frequency range of 2% around 14.1 GHz. The right handed circular polarized (RHCP) and the left handed circular polarized (LHCP) radiation components are compared at frequency 14.1 GHz in Fig. 4, where, it is clearly seen that the proposed antenna is RHCP along the broadside direction, with 6 dBi CP gain. The isolation between the RHCP and LHCP is more than 40 dB at θ=0˚. Fig. 5 shows that the peak gain variation of the only offset cross-slot at 14.1 GHz, which clearly indicates that this cross-slot is a non radiating slot at 14.1 GHz.
Fig. 3 S 11 (dB) parameter and axial ratio (dB) of the proposed antenna.
10
Phi=0deg Phi=90deg
Gain (dBi)
0
RHCP
-10
LHCP
-20
-30 -150 -100 -50
0
50
100
150
angle (deg)
0
Fig. 4 Radiation pattern of the proposed antenna in two principal planes at 14.1 GHz.
-20
1
-30
0 -40
-1
S11(dB)
Peak gain (dBi)
S-parameter (dB)
-10
S22(dB)
-50 10
12
14
16
18
20
Frequency (GHz)
Fig. 2 Return loss characteristics of the SIW structure.
-2 -3 -4 -5
.
-6 12
13
14
15
16
Frequency (GHz)
Fig. 5 Peak gain variation of the cross-slot.
176
12th International Conference on Microwaves, Antenna, Propagation & Remote Sensing ICMARS-2017, Jodhpur, INDIA, Feb. 15 – 17, 2017
IV. CONCLUSIONS The most important aspect of this work is the fact that a SIW fed CP DRA array can be designed for high frequency applications using this concept. Moreover, this work proffers a possibility of innovation of different types of slots to achieve wide AR bandwidth, especially for high frequency applications. So, there are different prospects of this work, and hence it requires further investigations. ACKNOWLEDGMENT The authors would like to express their thanks to University Grants Commission (UGC), Govt. of India for financial support. REFERENCES [1]
[2] [3]
[4]
[5] [6]
[7]
[8]
M. Bozzi, A. Georgiadis, and K. Wu, “Review of substrate-integrated waveguide circuits and antennas,” IET Microwaves, Antennas & Propagation ., vol. 5, pp. 909-920, 2011. A. Petosa, Dielectric resonator antenna handbook. Artech House Publishers, 2007. B. Rana and S. K. Parui, “Nonresonant microstrip patch-fed dielectric resonator antenna array,” IEEE Antennas Wireless Propag., Lett., vol. 14, pp. 747-750, 2015. B. Rana and S. K. Parui, "Hign gain circularly-polarized dielectric resonator antenna array with helical exciter," Progress in Electromagnetics Research Letters, vol. 46, pp. 107-111, 2014. B. Rana and S. K. Parui, “Dual-polarized dielectric resonator antenna array,” Microw. Opt. Technol. Lett., vol. 58, no. 1, pp. 24-27, 2016. B. Rana, A. Chaterjee and S. K. Parui, “Gain enhancement of a dualpolarized dielectric resonator antenna using polarization independent FSS,” Microw. Opt. Technol. Lett., vol. 58, no. 6, pp. 1415-1420, 2016. B. Rana and S. K. Parui, “Design of SIW series fed cylindrical dielectric resonator linear array antenna,” IEEE Int. Symp. Phased Array Syst. Technol., Boston, MA, USA, pp. 585–587, 2013. C. Y. Huang, J. Y. Wu, and K. L. Wong, “Cross-slot-coupled microstrip antenna and dielectric resonator antenna for circular polarization,” IEEE Trans. Antennas Propag., vol. 47, no. 4, pp. 605– 609, 1999.
177
