A low-cost diversity antenna switching system and method is realized by
controlling bias voltages on PIN diodes. By increasing the reverse bias
voltage impressed upon a PIN diode, an RF signal impressed upon the diode
is increasingly attenuated. As the PIN diode is forward biased to conduct
in the forward direction, RF attenuation decreases. Two or more PIN diodes
are used to increasingly attenuate signals from one antenna as attenuation
of signals from another antenna is gradually decreased. The progression of
the bias voltages is accomplished using a microprocessor that monitors a
received signal strength indicator (RSSI) signal from a radio receiver.
The RSSI is used to control which of two antennas are coupled into the
receiver by predicting a signal fade.
