We report on switching properties in the microwave region of yttrium hydride. A microstrip line of gold on a quartz substrate was used. A gap in the gold had an yttrium hydride layer of 1.0 ÎŒm thickness with a cap layer of 5 nm palladium and 2 nm aluminium oxide. The yttrium hydride was switched between a metallic and a semiconducting state with the exchange of hydrogen. The transmission (S21) and reflection (S11) coefficients were measured in the range 10 MHz-20 GHz. In the metallic state, the sample works like a microwave transmission line and in its semiconducting state, like a microwave resistor. The transmission coefficient was also measured at 5.0 GHz during hydrogenation and de-hydrogenation.