Waveguide Slot Filtering Antenna with Metamaterial Surface · 2018. 10. 19. · waveguide divider...
Transcript of Waveguide Slot Filtering Antenna with Metamaterial Surface · 2018. 10. 19. · waveguide divider...
Waveguide Slot Filtering Antenna with
Metamaterial Surface
Wei Wang, Zhi Zheng, Hong-tao Zhang, Mou-ping Jin, Ying Liu East China Research Institute of Electronic Engineering, Hefei, P. R. China
East China Research Institute of Electronic Engineering, Hefei, P. R. China
East China Research Institute of Electronic Engineering, Hefei, P. R. China
East China Research Institute of Electronic Engineering, Hefei, P. R. China
Science and Technology on Antenna and Microwave Laboratory, Xidian University, Xi’an, P. R. China
Abstract - Novel metamaterial waveguide slot antenna with
filtering performance is presented. The antenna is composed
of a rectangular waveguide, longitudinal slots cut in its upper broadwall and a metamaterial surface instead of the bottom broadwall. The antenna performs excellent filtering ability
using the matematerial surface, in the specified interfering band. And two kinds of the surface are described in this work. One is in the form of metal bed of nails while the other is
made up by periodic mushroom-type cell.
Index Terms — Filtering antenna, Waveguide slot antenna Metamaterial surface.
1. Introduction
With the eruptible development of the wireless
communication, electromagnetic compatibility (EMC)
problems are increasingly serious, which promotes the
development of anti-interference technology and has
attracted abundant research efforts [1]. Filtering antennas
[2]-[3], which have radiating and filtering functions
simultaneously, can effectively improve the anti-
interference performance of electronic systems so cater
for the demand. And compared with the traditional
design of cascading the filter right after the antenna,
filtering antennas have more compact structure, lighter
weight and lower cost.
Many kinds of design approaches of filtering antennas
have been reported. In [2], a bandpass filtering performance
was achieved by placing a parasitic loop at the top of a
printed antenna. Based on multilayer low-temperature
cofired ceramic (LTCC) technology, a quasi-elliptic filter
was integrated into a microstrip line to feed a series-fed
antenna array in V-band [3]. In our previous work, the
waveguide divider for broadenning the bandwidth of a
waveguide slot antenna array [4]-[5] offers a proper
structure to insert filters in the array, obtainning a filtering
antenna array [6]. Recently, a synthesis process for
filtering antenna design has been presented. In these
designs, the antenna not only radiates, but also serves as the
last resonator or the load impedance of the filter [7]-[8].
Nevertheless, in some designs, the filtering structure needs
extra circuit area, leading to large size. While in the others,
due to the lack of the exact extraction of the antenna’s
equivalent circuit, the filtering performance is limited.
In this paper, a waveguide slot filtering antenna using
metamaterial surface is proposed. The proposed filtering
antenna consists of a waveguide slot antenna and a
metamaterial surface embedded at the bottom of the
waveguide cavity. Different from the previous design
process, additional filter circuit is not necessary in our
approach. The rejection function at the interference
frequencies is achieved using the inherent bandgap of the
metamaterial surface.
2. Geometry of the filtering antenna
The geometry of the proposed waveguide slot filtering
antenna array is shown in Fig.1. The configuration is
similar to the conventional waveguide slot antenna, except
that the smooth metal plane in the bottom of the rectangular
waveguide is replaced by a metamaterial surface.
(a) with bed of nails
(b) with mushroom-type substrate
Fig. 1. Structure of the proposed filtering antennas
2018 International Symposium on Antennas and Propagation (ISAP 2018)October 23~26, 2018 / Paradise Hotel Busan, Busan, Korea
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The metamaterial surface can be achieved using many
kinds of periodic structure, such as bed of nails, as shown
in Fig. 1(a) and mushroom-type substrate, as shown in
Fig.1 (b).
At the operating frequencies, the metamaterial surface
performs as a perfect electric conductor (PEC), so the
antenna radiates just like the traditional waveguide slot
antenna. While in the interference band, the surface
performs as a perfect magnetic conductor (PMC), with the
height of the waveguide cavity less than 4S ( S is the
smallest wavelength of interference band), it can stop the
propagation of electromagnetic wave in the waveguide
cavity, so the interference signal is rejected and a filter
function is achieved.
3. Simulation results
Due to the limit of the extent and the similarity between
the antennas shown in Fig. 1(a) and Fig. 1(b), only the
simulated results for Fig. 1(b) will be shown here.
Firstly, the simulated transmission coefficient of the
metamaterial waveguide is plotted in Fig. 2. The
metamaterial waveguide is composed of a rectangular
waveguide and a mushroom-type surface replacing the
smooth metal plane at the bottom of the waveguide cavity.
As seen in Fig. 2, in the working band, it has a nearby-0dB
performance. While in the interference band, its value is
below -60dB, means the wave is strongly rejected. The
rejection function arrives because there is a bandgap for the
mushroom-type surface at the same frequency band.
Fig. 2. Simulated S21 of the filtering waveguide
Then, the filtering antenna is arrived cutting radiating
slots in the upper broadwall. Four slots are adopted in this
work. The offset and length of the slots are carefully
adjusted to meet good impedance matching and radiation
property. The received energy when illuminated by an
ultra-wide band horn is plotted in Fig. 3. Compared with
the value of -23dB in the working band, it is always below
-65dB in the interference band (over 7.90~8.75GHz), this
means a suppression level stronger than 40dB is achieved.
Fig. 3. Simulated received energy illuminated by an ultra-
wide band horn
4. Conclusion
A novel design approach of waveguide slot filtering
antenna is presented. The filtering function is obtained
using the bandgap property of the metamaterial surface,
which is embedded at the bottom wall of the waveguide
cavity. A 4-slot antenna is designed and the excellent
simulated results have verified the innovative method
Acknowledgment
This work was supported by the National Natural Science
Foundation of China under Grant 61671416.
References
[1] B. Froppier and S. Toutain. "Distribution of the radiation function on the filter structure." Antennas and Propagation Society International
Symposium IEEE, 2005, PP. 704-707, vol. 3A.. [2] J. Wu, Z. Zhao, Z. Nie, and Q.-H. Liu, “A printed unidirectional
antenna with improved upper band-edge selectivity using a parasitic
loop,” IEEE Trans. Antennas Propag., vol. 63, no. 4, pp. 1832–1837, Apr. 2015.
[3] J.-H. Lee, N. Kidera, S. Pinel, J. Laskar, and M. M. Tentzeris, “Fully integrated passive front-end solutions for a V-band LTCC wireless
system,” Antennas Wireless Propag. Lett., vol. 6, pp. 285–288, 2007..
[4] W. Wang, S.-S Zhong, Y.-M Zhang and X.-L Liang, “A broad bandwidth slotted ridged-waveguide antenna array,” IEEE, Trans.
Antennas Propag., AP-54, pp:2416-2420, 2006, [5] W. Wang, S.-S Zhong, M.-Q. Qi, and X.-. Liang, “Broadband ridge-
waveguide slot antenna array fed by a back-to-back ridged
waveguide,” Microwave and Optical Technology Let., Vol.45, no. 2, pp:102-104, 2005.
[6] W. Wang, L. Li, H.-T. Zhang, Z.-H. Zhang, “Frequency selective broadband waveguide slot antenna array,” China Patent
CN200910116834.8.
[7] Y. Yusuf and X. Gong, “Compact low-loss integration of high-Q 3-D filters with highly efficient antennas,” IEEE Trans. Microw. Theory
Techn., vol. 59, no. 4, pp. 857–865, Apr. 2011. [8] C. K. Lin and S. J. Chung, “A compact filtering microstrip antenna
with quasi-elliptic broadside antenna gain response,” Antenna
Wireless Propag. Lett., vol. 10, pp. 381–384, 2011.
2018 International Symposium on Antennas and Propagation (ISAP 2018)October 23~26, 2018 / Paradise Hotel Busan, Busan, Korea
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