Deliverable 9.2: Technical report on the T/R switch design
Task 9.3 of the EISCAT_3D Preparatory Phase is concerned with the verification and evaluation of the transmitter/receiver switch design.
Deliverable 9.2 is a report covering the design and testing of a T/R switch realised on microstripline technology. The tested switch mainly meets the deign goals for use in the EISCAT_3D system. As designed, the prototype T/R switch meets the power handling and switching time design targets. It also approaches the isolation and loss targets to within acceptable tolerances, considering the intended application:
- At 350 W incident power, only -20 dBm leaks through to the receiver; this is about 10 dB less than the level that low noise HEMTs can withstand indefinitely without degradation
- With a sky temperature exceeding 200 K and a receiver noise temperature of more than 35 K, an extra 15 K noise temperature added by the T/R switch (36 K instead of 21 K) translates to a signal-noise ratio loss of less than 6 %
Addendum: When this Deliverable was originally reported, the high power tests of the T/R switches had failed since the used PIN-diodes did not withstand the required power. The design criteria parameters presented in the Deliverable confirmed that the operating conditions for the PIN-diodes with some margin were within those presented in the data sheets issued by the manufacturer (MA/Com). Contact with MA/Com was established, and another PIN-diode version was put into the case type that fitted our design (the new version was originally not available in the “micro strip” case we had selected). The conclusion after the 1000 hours continuous test is that the design works according to the design specifications and targets as given in the baseline documents.