An improved dual-band shared aperture waveguide slot array antenna

In this article, an improved C/X band shared aperture waveguide slot array antenna with orthogonal polarizations is designed. The waveguide narrow-edged inclined slots are used to realize the X-band antenna array located in the upper layer. The waveguide wide-edged longitudinal slots are used to realize the C-band array located in the lower layer. A novel T-shaped transition cavity is placed in the middle of two antennas to reduce the shadowing effect of X-band on C-band antenna. To verify the design method, a 3 x 3 C-band array integrated with a 16 x 30 X-band array is discussed in detail. The measured -10 dB return loss bandwidth of C-band antenna is 300 MHz. The maximum gain is 17.6 dB at 5.5 GHz with the aperture efficiency of 85%. The good agreements between simulations and experiments demonstrate that the proposed C/X band shared aperture array antenna is a novel and effective method for dual-frequency waveguide slot array. It presents an excellent candidate for dual frequency antenna with large frequency ratio and high power capacity.