A Compact Frequency Scanning Planar Array Using Characteristic Mode Analysis

In this letter, a compact planar array with frequency scanning characteristics is proposed. Based on the characteristic mode analysis (CMA), we found that there distribute four modes with distinctive radiation patterns and phase characteristics. And combining them in pairs would generate scanning beams within a narrow band. In addition, CMA offers us useful guidelines on enhancing the gain and suppressing the sidelobes. A prototype was fabricated and measured. Under the excitation of a single port, namely P
₁
, the scanning range was from 14
^°
to 51
^°
with sidelobe level (SLL) lower than -20 dB. As switching the port from P
₁
to its symmetrical port, P
₂
, the scanning scope in the E-plane would be extended to the mirrored space from -14
^°
to -51
^°
.