A frequency reconfigurable patch antenna using reed switches to connect the patch with the ground plane is proposed. Compared with other voltage-controlled switches like MEMS and PIN diodes, reed switches are controlled by a magnetic field which can penetrate the ground plane easily. In this way, the control circuit can be placed beneath the ground plane to avoid its impacts on the radiation performance of the antenna. Twenty-four reed switches are used to increase the reconfigurability of the antenna and to show the feasibility of our concept when multiple control circuits are used simultaneously. The presented antenna can be reconfigured to operate in the frequency range from 0.3 to 3 GHz, covering for a large number of communication services. Three operating modes of the antenna (with resonance frequencies at 0.8, 2, and 2.85 GHz, respectively) are presented to illustrate the feasibility of this method. The measured matching and radiation characteristics of the fabricated antenna prototype agree well with the simulations.

An X-band active phased array horn antenna with high power capacity and high peak power is proposed in this paper. At the horn aperture, the baffles are loaded to suppress higher-order modes and eliminate blind spots during beam scanning. Straight walls are added to improve impedance matching. Considering that the peak power that T/R modules can provide is very limited, the proposal of a dual-port waveguide breaks through the bottleneck of the power capacity of a single-port input for the first time. The proposed curved dual-port waveguide is used to connect the horn antenna and the T/R module, which is verified to improve the power capacity of the overall internal structure. Simulated and measured results show that VSWR ≤ 2 in the frequency range of 7.5–8.5 GHz. There is no grating lobe in the ±10° scanning range and the maximum gain drop does not exceed 0.4 dB. The power capacity of the proposed HPM array is 56.34 MW. The phased array antenna has the characteristics of flexible scanning, small size, and high gain, and can be applied in high-power microwave systems.