In this paper, a wideband OAM antenna array for wireless communication is proposed, which has a wide impedance bandwidth and can cover the S-C band with a relative bandwidth of 61.58%. The measured gain can reach 7.81 dBi and the radiation efficiency can reach 74.7%. Compared with similar antennas, the antenna array has a metal back cavity as the supporting structure, which further improves the structural stability of the array. The array adopts Z-shaped parasitic radiation units, a ring-shaped stepped metal reflection back cavity, and other structures. These can be verified to improve the performance of the array after design analysis and testing. In addition, the performance enhancement of a conventional Wilkinson divider by adding the S-shaped parasitic radiation patch is analysed by parameter scanning. The array is robust, simple to process, and easy to integrate. It can maximise its value in the crowded retrofit space of wireless antennas.

High-power mainlobe jamming severely degrades the target-detection capabilities of array radars in complex electromagnetic environments. Although the difference-channel signal can be reused as an auxiliary reference to suppress the jamming component in the sum channel, the jamming component remains unmitigated in the measured difference channel of a three-channel radar without a dedicated difference–difference channel, thereby introducing additional angle-estimation errors. Addressing this, this study analyzes a subarray-level, three-channel monopulse array radar. Based on a one-dimensional uniform linear array and the sum–difference monopulse principle, we formulate a joint model for mainlobe jamming cancellation and angle estimation. We then evaluate how the jammer azimuth, jamming-to-signal ratio (JSR), number of jammers, and radar operating modes (search and tracking) affect the resulting angle error. Simulation results indicate that in search mode, cancellation restores local angle-estimation capabilities near the target direction. When the beam points near the jammer, the jammer approaches the null of the auxiliary difference beam, weakening the reference signal and causing pronounced nonmonotonic distortion in the angle-estimation curve. In tracking mode, the cancellation process yields smaller angle errors and increased stability. A two-element 4.03 GHz anechoic-chamber experiment completes the proof-of-principle validation for the core mechanism under the single-jammer search-mode scenario. These findings define the operational boundaries of using the difference-channel signal as an auxiliary reference for sum-channel jamming cancellation in three-channel radars, providing a theoretical foundation for angle-error compensation, receiving-channel design, and the refinement of interference cancellation techniques.