PORTLAND, Ore.Concealing narrow-bandwidth antennas inside a mobile device gets tricky when they need to be tuned for different servicesfrom cell phone to Bluetooth to WiFi to mobile TV.
Peregrine Semiconductor Corp. (San Diego, Calif.) claims to be unveiling the first single-chip solution at Electronica 2008 (Munich, November 11-14, 2008).
Peregrine's digitally tunable capacitor chip aims to adjust a mobile antenna's radio-frequency (RF) response to all the different bands mobile media devices receive today. Potentially, it can also dynamically tune even for environmental changescountering effects like touching your finger to the antenna.
Microelectromechanical systems (MEMS) devices integrating RF are being developed by WiSpry Inc. (Irvine, Calif.) and NXP, and ferroelectric devices are also being developed.
But Peregrine's CMOS Dune (for digital tune) process is here and now. Leveraging its switching FET's already widely used to reconfigure radio circuitry for the different cell phone bands, Peregrine conceived Dune to enable what it claims is the first single-die tunable capacitor.
Monolithic integration of RF, analog and digital circuitry uses Peregrine's proprietary silicon-on-sapphire CMOS process to isolate linear, high-Q tunable capacitors capable of 32-levels of capacitance under the control of a five-bit register.
Typical capacitance values range from 0.5pF to 10pF, with tuning ratios ranging from 3:1 to 6:1, +38 dBm of power handling at 50 Ohm, and switching speed of better than 5 microseconds.