Design of a Concentric Array Radial Line Slot Antenna for High-Power Microwave Application

A compact concentric array radial line slot antenna (CA-RLSA) operating at K
_u
-band for high-power microwave (HPM) application is proposed in this paper. The efficiency of HPM-RLSA becomes lower as the aperture size reduces due to rotational asymmetry of the illumination. The HPM-CA-RLSA was designed to overcome this difficulty with notable power handing capacity. It is fed by circularly polarized TE11 coaxial waveguide mode to generate a rotational symmetric cylindrical wave excitation. Furthermore, the reflection canceling structure of this HPM-CA-RLSA is not only simpler than the one in the HPM-RLSA but also improves the frequency response performance. An antenna prototype with length of 8 cm and aperture diameter of 40 cm is designed, which has a gain of 32.0 dBi, reaching an aperture efficiency of 62.7%, and an axial ratio less than 0.5 dB at 12 GHz. The simulated results show that this antenna has a power handing capacity of more than 500 MW.