LAUSR

A new design of coaxial rotary joint (RJ) made compact by applying “folded” choke quarter-wave impedance transformer is proposed for very high-frequency surveillance radar. The final prototype, which measures L $388\,\,\text {mm} \times \text {D}\,\,106$ mm, demonstrated 0.04-dB insertion loss and 28-dB return loss within the operating frequency range of 150–170 MHz. The RJ is able to handle peak power of 15 kW during experiments. By avoiding reliability issues inherent in contacting RJ, the lifetime and stability of the whole radar system would be remarkably enhanced.