LAUSR

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 × 3 C‐band array integrated with a 16 × 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.