Switching RF signals

Modern RF relays have to carry and to switch DC as well as AC and RF signals with frequencies up to the GHz range. While the switching phenomena for switching DC loads or low frequency AC loads are very well known, only very limited information is available for switching RF signals up to 5 GHz. Basic considerations about relevant phenomena for switching RF signals are made and compared with the already well-known effects, when DC or low frequency AC signals are switched. Practical tests were performed on a new type of high performance low-cost ultra-miniature RF relay with DC loads up to 60 W, low frequency AC loads up to 62.5 VA and RF loads with a maximum power of 50 W. The results obtained confirm the theoretical approach. Major advantages of bridge contacts providing two contact gaps in series were found, yielding excellent RF characteristics as well as outstanding switching performance in all frequency ranges from DC to RF.