Design of Heterogenous Two-Element Array Antenna on an Electrically Thick Substrate for High Isolation and Low Pattern Correlation Using Modal Difference in Radiation Patterns

Abstract

In this paper, we propose a novel design of a two-element array antenna on an electrical thick substrate with an extremely narrow array distance. The proposed array consists of a rectangular ring patch printed on a thick substrate and a monopole wire in the center of the substrate. Each element has a modal difference in the radiation pattern, causing high isolation and low correlation between the array elements. From the measurement results, the monopole and patch elements exhibit reflection coefficients of −10 dB and −10.7 dB with peak gains of 3.8 dBi and 6.1 dBi, respectively, at 1.6 GHz. The mutual coupling between the two elements is −20.7 dB. For modal analysis of the antenna pattern, spherical mode decomposition is performed on the radiation patterns of the two elements, and low envelope correlation coefficient levels below 16% are maintained. We also investigate the antijamming performance using a power inversion algorithm in a practical pattern nulling application; a null depth of −47.7 dB and a null width of 33.2° are obtained when the interference signal arrives at the elevation angle of 45°.

Antenna Design for Microwave and Millimeter Wave Applications: Latest Advances and Prospects

“…Lim et al [1] proposed a novel design of a two-element array antenna on an electrical thick substrate with an extremely narrow array distance. The proposed array consists of a rectangular ring patch printed on a thick substrate and a monopole wire in the center of the substrate.…”

Triple‐mode resonant null frequency scanning antenna with positive scanned slope

“…A square patch antenna under hybrid “fixed‐tunable” loading 18 can also offer similar functionality. The third way should be the combination of multiple single‐mode resonant radiators 19–27 . Under multi‐port excitations, broadside and conical modes of different single‐mode resonant radiators can be flexibly combined to generate steerable radiation nulls 19–23 .…”

“…Using concentric circular patch/annular rings under single‐mode resonance, distinctive amplitude/phase excitations may also generate a narrow band null scanning functionality 24–27 . In these designs, external multi‐port feed networks are required to generate the desired amplitude/phase conditions 19–27 . More recently, a wideband null frequency scanning circular sector patch antenna has been advanced 28,29 .…”

“…More recently, a wideband null frequency scanning circular sector patch antenna has been advanced 28,29 . Unlike those presented in References 19–27, multiple resonant modes within single microstrip patch radiator can be simultaneously excited by a single port. When a complementary patch is properly incorporated, the radiation null can continuously scan without blind zone over a wide frequency range of 24.0% 28 .…”

“…The third way should be the combination of multiple single-mode resonant radiators. [19][20][21][22][23][24][25][26][27] Under multi-port excitations, broadside and conical modes of different single-mode resonant radiators can be flexibly combined to generate steerable radiation nulls. [19][20][21][22][23] Using concentric circular patch/annular rings under single-mode resonance, distinctive amplitude/phase excitations may also generate a narrow band null scanning functionality.…”