| 摘要 |
PURPOSE:To decrease the insertion loss between input and output terminals and to provide an excellent input/output impedance by forming a high frequency switch with >=3 sets of 90 deg. hybrids and a couple of 1st and 2nd switching elements. CONSTITUTION:Three sets of 3dB directivity couplers 21 using parallel coupling lines are provided as the 90 deg. hybrids. Two FETs 22, 23 are used as a switching circuit. Terminals 24, 25, 26 are used as input/output terminals. When the FET22 is conductive and the FET23 is cut off, most of input power to the terminal 24 is outputted to the terminal 25 but the terminal 26 has little input power. The FET23 is connected respectively to terminals 241, 242 and the same load impedance is given, then no reflected wave appears at the terminal 24 and all the reflected wave is absorbed to a termination resistor 29. Thus, the propagation loss from the terminal 24 to the terminals 25, 26 is decreased. |
