Ku-Band Small-Frequency-Ratio Self-Diplexing Vivaldi Antenna With High Isolation for High-Power Application

A Ku-band small frequency ratio (FR) self-diplexing Vivaldi antenna with high isolation for high-power application is presented. It consists of two structural components sandwiching a post-wall Vivaldi antenna (PVA). A high-performance dual-band diplexer is integrated into the PVA without increasing the antenna layout area, which effectively reduces the size and complexity of RF front-end. Two filtering circuits are separately etched on the PVA to realize self-diplexing. High isolation is obtained under a small FR through adopting the cross-coupling topology in filtering circuits design. The two structural components not only serve as the ground of suspended stripline structure (SSS), shielding the filtering circuits, but also enhance the gain of the antenna. Benefiting from SSS, both high power capacity and low insertion loss are achieved. A prototype is designed and fabricated to verify the principles. The measured results show that a high isolation better than 56 dB is achieved in Ku band, with a small FR of 1.23. The proposed antenna is suitable for long-distance communication systems such as satellite communication systems.