Characteristic Mode Analysis of a Ka-Band CPW-Slot-Couple Fed Patch Antenna with Enhanced Bandwidth and Gain

A Ka-band CPW-Slot-Couple (CSC) fed microstrip antenna with enhanced bandwidth and gain is presented in this paper. To simplify the feed network, the matching slots are designed at the end of the CPW. Consequently, the patch antenna is designed with a low profile, which has a size of 7.2 x 32.6 x 0.508 mm(3). Characteristic mode analysis (CMA) is applied to illustrate the principle of the enhancement of the band with the form characteristic mode point of view. A slot based on inductive loading is employed on the parasitic patch to move the resonant frequency of CM3 to the resonant frequency of CM2 for enhanced bandwidth, which avoids introducing additional impedance matching networks. The measured results show that the bandwidth of the proposed monolayer antenna is 14.18% from 24.84 to 28.6 GHz and the peak gain is 7.9 dBi. Due to its attractive properties of low profile, compact configuration, wide band, and high gain, the proposed antenna could be applied to miniaturized millimeter-wave applications.