This article presents a novel tightly coupled dipole array (TCDA) with a bandwidth of 26.2:1 (VSWR < 3) across 0.20–5.23 GHz. By adding a new dual-stopband resistive frequency selective surface (RFSS) between the dipole and the floor, the short-circuit points formed by the floor at the frequency points corresponding to λ = 2 h and h are both eliminated (h is the height from the antenna to the floor). A specially integrated feed network is also applied to significantly reduce the complexity and profile height to 0.05 λ_low. The simulation and experimental results show that the designed TCDA has extremely wide bandwidth, good directivity and beam scanning potential. Compared with previous designs, it greatly extends the bandwidth, improves the gain, reduces the profile height, and simplifies the feeding method.

This paper proposes a monostatic transceiver system based on a pure waveguide structure. The designed beamforming network (BFN) and polarization direction regulators enable the system to use the same waveguide path and antenna for both transmission and reception. Furthermore, the output polarization direction can be adjusted to any arbitrary angle. Simulation results indicate that the waveguide structure provides a power capacity exceeding 500 kW. Measurements demonstrate that within the 9.85–10.15 GHz band, the system achieves a voltage standing wave ratio (VSWR) of ≤2.1, an isolation of 29–52 dB, and a gain of 14.8–16.7 dBi.

This article presents a low-power measurement method for the reflected power of a high-power millimeter-wave dummy load. The proposed method extracts the unknown S-parameters of the fixtures and the dummy load by combining frequency-and time-domain S-parameters. In this way, it partially eliminates the effects of asymmetric fixtures. Experiments and error source analysis of the proposed method are carried out.