High-Order Mode Cavity Filtering Antenna Array Based on Wavefront Phase Compensation

In order to solve the problem of large sidelobes in traditional high-order mode cavity slot antenna design, an effective method based on wavefront phase compensation is proposed in this paper. Two compensation methodologies, wavefront phase advance and wavefront phase lag, are given and analyzed in detail. By combining the two compensation methods, the wavefronts of adjacent elements with opposite phases can be transformed into those with the same phase, achieving broadside beam. In addition, the relationship between the directivity and radiation quality factor of the radiation structure is discussed in detail, which is used to solve the problem of different gains of the radiation elements in the array. For verification, a first-order filtering antenna array with five elements and a fifth-order filtering antenna array with ten elements are designed using TE 501 mode cavity. The fifth-order filtering antenna array is fabricated and measured. The measured gain in the passband is stable and the maximum gain is 17.3 dBi. The simulated results are in good agreement with the measured ones, which indicates that the proposed method can be used to design a filtering cavity slot antenna array with high gain and low sidelobes.