IEC 62047-41:2021 pdf download – Semiconductor devices – Micro-electromechanical devices – Part 41: RF MEMS circulators and isolators.
5.1.4 Handling precautions The RF MEMS circulator/isolator devices in this document are chip types or packaged device types. Before measurement, the devices should be suitably packaged and mounted on a test fixture and measured by using a vector network analyser. Since the impedance of the network analyser is usually 50 Ω, the termination condition between the RF MEMS circulator/isolator and the equipment should be considered carefully. Before connecting the RF MEMS circulator/isolator to the test fixture, the network analyser, cable, and connectors should be calibrated. The full 2-port calibration technique is effective to compensate the system errors (i.e. presenting open-circuit impedance, short-circuit impedance, through standards at the ends of test cable connectors, 50 Ω load impedance, and storing the measured values for correction of the RF MEMS circulator/isolator measurement). After calibration, connect the test cable with the circulator/isolator test fixture with 50 Ω connectors. The reading of S-parameter on the display of the network analyser is taken. A reflection coefficient S and a transmission coefficient S translated into reflection attenuation and insertion attenuation, respectively. of 2-port S-parameters are 11 21 If a different frequency range is required, the entire calibration sequence shall be repeated. 5.2 Insertion loss ( L ins ) 5.2.1 Purpose To measure the insertion loss under specified conditions. 5.2.2 Circuit diagram Measuring methods should be selected properly according to the network analyser, which may provide two or more ports for testing. a) Method A): with the 4-port network analyser: 1) The measuring circuit diagram for the insertion loss measurements of the circulator is shown in Figure 4. The circulator is a 3-port device, taking the 4-port network analyser. And the fourth port of the network analyser should be properly terminated during testing.
d) The network analyser should be pre-set and set up to the standard S-parameters measurement class, where selecting the transmission measurements ( S 21 , S 32 and S 13 ): 1) Specify the frequency range of the signal source, which is the span of frequency for making a device measurement, including start frequency, stop frequency, number of measurement points, etc.; 2) Specify the frequency sweep type of the signal source, using linear frequency sweep type typically; 3) Specify the power level of the signal source to proper value; 4) Specify the display format, usually using “Log Mag” display format. e) Perform measurement: 1) Scale the displayed measurement for optimum viewing; 2) Read the S-parameter (S , S and S 13 ) values. Each parameter values at each 21 32 frequency point are the insertion loss: L ins(21) = S 21 , L ins(32) = S 32 and L ins(13) = S 13 . 5.2.5.2 Method B): with the 2-port network analyser, the measurement procedures are as follows: a) The RF MEMS circulator/isolator should be suitably packaged and mounted on a test fixture; b) The test fixture, the network analyser, cable, and connectors should be calibrated before performing measurement; c) The test fixture should be connected to the network analyser using the test cable with 50 Ω connectors. For circulators, connected as shown in Figure 6 a); for isolators, connected as shown in Figure 7; d) The network analyser should be pre-set and set up to the standard S-parameters measurement class, where selecting the transmission measurements ( S 21 ):
1) Specify the frequency range of the signal source, which is the span of frequency for making a device measurement, including start frequency, stop frequency, number of measurement points, etc.; 2) Specify the frequency sweep type of the signal source, using linear frequency sweep type typically; 3) Specify the power level of the signal source to proper value; 4) Specify the display format, usually using “Log Mag” display format. e) Perform measurement: 1) Scale the displayed measurement for optimum viewing; 2) Read the S-parameter (S 21 ) values. Each parameter values at each frequency point are the insertion loss: L ins(21) = S . u f) Measuring insertion loss L ins(13) : The circulator should be connected as shown in Figure 6 b). Repeating procedures d) to e), each parameter values of S 21 at each frequency point are the insertion loss: L ins(13) = S 21 g) Measuring insertion loss L ins(32) . : The circulator should be connected as shown in Figure 6 c). Repeating procedures d) and e), each parameter values of S 21 at each frequency point are the insertion loss: L ins(32) = S 21 . 5.2.6 Specified conditions The specified conditions are as follows: a) frequency range; b) input power level.