Design of a Novel Compact Slotted Cavity With Shaped Beam for High Power Microwave Feed Antenna Using Asymmetric High Order Mode

In order to achieve a shaped beam on a compact aperture and reduce the cost and the volume, a conformal slotted cavity as a feed antenna for high-power microwave using the asymmetric high-order mode is investigated. The proposed antenna working in a high-order mode has merits on reducing the complexity of a power network and the volume of a mode converter. The alternate arrangement of the slot array is taken into account, and the asymmetric high-order mode TE430 is selected to improve the symmetry of far-field pattern at the E-plane. A novel design of wide slot with the horn-cavity etched on the top surface of the upper cavity achieves the uniform aperture field and mitigates the maximum electric field enhancement, and calculated results verify that the proposed antenna is capable of high-power handling capability (above 1.29 GW in vacuum). The conformal slot array is introduced to obtain a shaped beam, which helps to illuminate reflect array with shaped aperture efficiently. The simulation and measured results show that the feed antenna achieves a low-profile structure of 2.44 lambda(0) x 2.8 lambda(0) x 0.8 lambda(0), the 10-dB gain beamwidth of E-plane is 56.6 degrees at the operating frequency of 9.1 GHz, the maximum difference of the gain, and the 10-dB beamwidth angle between the two sides of main beam is no more than 1 dB and 1 degrees, respectively.