RF Solid State Switch
In this project, I wanted to design an RF switch that I could use for low power switching, especially at intermediate frequencies. Solid-state switches have several benefits in comparison with electromechanical switches such as better reliability, longer lifetime, resistance to mechanical vibrations and shocks, and they allow fast switching. On the other hand, solid-state switches have greater parasitic resistance, so they have higher insertion loss. Good quality mechanical relays can be very expensive therefore this could be a good alternative for some projects. My first proptotype can be seen in the following pictures. I chose a non-reflective DC to 4 GHz GaAs MESFET SPDT switch (HMC435AMS8GE). Soldering of the package (HMSOP-8) was a bit challenging and I had to use a microscope for it. The switch is connected to the SMA connectors through blocking capacitors (100pF, 0402 package). Based on the measurement I found that there is better impedance matching needed between the SMA connector and the coplanar waveguide, so it will be improved in my future design.