A Single-Layer Probe-Fed Reference Antenna With Broadband and Stable Gain

In this letter, a single-layer probe-fed reference antenna with broadband and stable gain is proposed. By establishing geometric relationships between the substrate-integrated cavity (SIC) and the patch antenna, the design effectively combines the advantages of the SIC for surface wave suppression with a multi-mode patch antenna configuration. A wideband differential feeding network integrates two phase-shifting structures, maintaining the phase difference of 180° ± 20° within the bandwidth to ensure the stable gain performance after the formation of the array. Experimental results demonstrate that the proposed antenna array can achieve a 30.2% (24.2–32.8 GHz) impedance bandwidth and a peak gain of 11.7 dBi. 3-dB gain bandwidth is 28.4% from 24.2 to 32.2 GHz, and the measurement results agree well with the simulation results.