Austin, Texas - XCom Wireless Inc. has begun sampling packaged MEMS-based relays and varactors that achieve 18-GHz frequencies, the company said, with Q factors in the 150 range. The parts will target phased-array antennas in the military.
Initially offering phase shifters and tunable filters for the antennas, XCom will zero in on radar, missiles and satellite systems and wireless handsets in military use, said Richard Sweet, director of product development at XCom (Signal Hill, Calif.).
Eventually, the microelectromechanical systems (MEMS) components could go into lower-cost phased-array antennas for collision avoidance and adaptive cruise control systems in automobiles, as well as in mobile broadcast satellite antennas.
The MEMS devices, pictured above, enable passive phased-array antennas, in which the expensive transmit and receive (T/R) module can receive signals from many different relays and filters. In conventional or active phased-array antennas, each relay is matched with a T/R module in an expensive package, driving costs for phased-array antennas into the hundreds of thousands of dollars, said Roger Kuroda, vice president of engineering. Kuroda presented XCom's technology at the recent Software-Defined Radio Forum here.
XCom has received several prototype wafers of its MEMs relays and varactors, with about 2,000 devices on each wafer. It uses two U.S.-based foundries, which Kuroda declined to identify, and expects to move into commercial production late this year.
The relays create a phase shift in the path of the transmitted signal for systems operating in the Ku band. The devices now being sampled include a variety of relays, including single-pole, single-throw (SP-ST) architecture, as well as double-throw and 4T relays. The MEMS devices include three-finger and nine-finger structures.
Founded by MEMS packaging authority Dan Hyman, XCom has received most of its funding from the Defense Advanced Research Projects Agency and several military system development groups. It also has received venture capital funding from the Ardesta firm in Detroit. Xcom employs about 15 people at the Signal Hill site, near Long Beach.
MEMS-based relays can hit higher frequencies than are possible with either CMOS or silicon-germanium-based PIN diodes.
"Our objective is to produce integrated subsystems with our MEMS technologies, to redesign the MEMS for particular applications," Sweet said, adding that it is difficult to survive as a component supplier that does not offer targeted subsystems.
MEMS with ohmic contacts (for relays) take less power to latch than capacitance-based devices (varactors), Kuroda said. Both offer low insertion loss. Because MEMS structures are either open or closed, they avoid the problem of secondary harmonics that come from PIN diodes, which rely on doped structures.