The RF switch (RF switch) is a very important component for testing the RF DUT, because the signal test direction needs to be planned during the test. RF Sw has evolved from basic SPDT, SP4T, SP6T, SP8T to multiple input and multiple output, various switchers for different test needs Subdivided mechanical type & electronic type & mechatronic type, the output port is also divided into "open circuit terminal resistance type" or "standard open circuit without terminal resistance"