Bah, AO, Qin, PY, Ziolkowski, RW, Guo, YJ & Bird, TS 2019, 'A Wideband Low-Profile Tightly Coupled Antenna Array with a Very High Figure of Merit', IEEE Transactions on Antennas and Propagation, vol. 67, no. 4, pp. 2332-2343.View/Download from: UTS OPUS or Publisher's site
© 1963-2012 IEEE. A wideband, low-profile, tightly coupled antenna array with a simple feed network is presented. The dipole and feed networks in each unit cell are printed on both sides of a single RT/Duroid 6010 substrate with a relative dielectric constant of 10.2. The feed network, composed of meandered impedance transformer and balun sections, is designed based on Klopfenstein tapered microstrip lines. The wide-angle impedance matching is empowered by a novel wideband metasurface superstrate. For the optimum design, scanning to 70° along the E-plane is obtained together with a very high array figure of merit P A = 2.84. The H-plane scan extends to 55°. The broadside impedance bandwidth is 5.5:1 (0.80-4.38) GHz with an active voltage standing-wave ratio value ≤2. The overall height of the array above the ground plane is 0.088λ L, where λ L is the wavelength at the lowest frequency of operation. A prototype was fabricated and tested to confirm the design concepts.
Bah, AO, Qin, P-Y, Ziolkowski, RW, Cheng, Q & Guo, YJ 2018, 'Realization of an Ultra-thin Metasurface to Facilitate Wide Bandwidth, Wide Angle Beam Scanning.', Scientific reports, vol. 8, no. 1.View/Download from: UTS OPUS or Publisher's site
A wide bandwidth, ultra-thin, metasurface is reported that facilitates wide angle beam scanning. Each unit cell of the metasurface contains a multi-resonant, strongly-coupled unequal arm Jerusalem cross element. This element consists of two bent-arm, orthogonal, capacitively loaded strips. The wide bandwidth of the metasurface is achieved by taking advantage of the strong coupling within and between its multi-resonant elements. A prototype of the proposed metasurface has been fabricated and measured. The design concept has been validated by the measured results. The proposed metasurface is able to alleviate the well-known problem of impedance mismatch caused by mutual coupling when the main beam of an array is scanned. In order to validate the wideband and wide scanning ability of the proposed metasurface, it is integrated with a wideband antenna array as a wide angle impedance matching element. The metasurface-array combination facilitates wide angle scanning over a 6:1 impedance bandwidth without the need for bulky dielectrics or multi-layered structures.
Bah, AO, Ziolkowski, RW, Qin, PY & Guo, YJ 2018, 'Design and Analysis of a Wide Angle Impedance Matching Metasurface for Wideband Antenna Arrays', 12th European Conference on Antennas and Propagation (EuCAP 2018), European Conference on Antennas and Propagation, IET, London.View/Download from: UTS OPUS or Publisher's site
A wide bandwidth, low profile, double sided, wide angle impedance matching metasurface is reported. It alleviates the well-known problem of impedance mismatch caused by mutual coupling when an array is in its scan mode. Each unit cell of the metasurface contains two multi-resonant, tightly-coupled unequal arm Jerusalem cross elements on the top and bottom sides of a thin substrate. Each element consists of two orthogonal capacitively loaded strips. The wide bandwidth of the metasurface is achieved by tightly coupling these multi-resonant elements. The metasurface is capable of facilitating wide angle scanning over a 6:1 impedance bandwidth without the need for bulky dielectrics or multi-layered structures.
Bah, AO, Qin, P & Guo, J 2016, 'An Extremely Wideband Tapered Balun for Application inTightly Coupled Arrays', Proceedings of the 2016 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), IEEE, Cairns, Australia.View/Download from: UTS OPUS or Publisher's site
This paper presents the design of a single layer, compact, tapered balun with a >20:1 bandwidth and less than λ/17 in length at the lowest frequency of operation. The balun operates from 0.7GHz to over 15GHz. It can provide both impedance transformation as well as a balanced feed for tightly coupled arrays. Its performance is compared with that of a full-length balun operating over the same frequency band. There is a high degree of agreement between the two baluns.
Yang, X, Zhao, G, Hu, W, Guo, YJ, Yin, YZ & Bah, AO 2016, 'Characteristics of wideband phased array with two-layer metasurface', Proceedings of the 2016 18th International Conference on Electromagnetics in Advanced Applications, ICEAA 2016, International Conference on Electromagnetics in Advanced Applications, IEEE, Cairns, Australia, pp. 852-855.View/Download from: UTS OPUS or Publisher's site
© 2016 IEEE.The agile beam scanning ability is attractive feature of phased array over traditional mechanical array, but it is difficult to achieve perfect impedance matching in all the directions. Furthermore, phased array capable of wideband operation is desired in multi-function radar and modern communication systems. In this paper, a wideband tightly coupled array models equipped with two-layer metasurface is presented and its characteristics are investigated. The metasurface consists of two substrates each printed with different periodic metallic patches to accommodate wideband and wide angle applications. The results show that, with the assistance of this artificial metasurface, the phased array can operate over a 5:1 ratio impedance bandwidth (VSWR<3) and the scanning angle is as large as 45°.