Linearity and RF Power Handling of Capacitive RF MEMS Switches

Linearity characteristics of capacitive tuners are an important issue for today’s cellphone market. Antenna tuners have become necessary in mobile devices due to the RF spectrum expansion in the low frequency range. Capacitive tuners connected directly to the antenna change the RF voltage/current pattern and are thus exposed to large voltage swings, especially in the isolation state (minimum capacitance). In this paper, we analyze the effects of high RF power on capacitive MEMS switches. Measurements up to 6.4W were performed in the isolation state (minimum capacitance) showing the robustness of this technology under large RF power or voltage swings. Measurements demonstrated IP3 of +125dBm for a 45MHz tone spacing and third harmonic of -136dBm at +38dm of incident power.