Enhancement of sensitivity of RF modules for wireless health care and home security systems

An effective way to enhance the sensitivity of an RF module for wireless health care (and home security) products is reported. The RF module (followed by a microcontroller unit) consists of an RF front-end, an radio frequency integrated circuit (RFIC), and a baseband data recovery circuit (DRC). The RF front-end comprises a power amplifier (PA) output matching network to enhance the output power of the PA, and a low-noise amplifier (LNA) input matching network to improve the sensitivity of the LNA. The baseband DRC comprises a multiple feedback low-pass filter to suppress out-of-channel noise/interference, and a comparator for rail-to-rail digital data recovery. This in turn results in an enormous enhancement of sensitivity (or operation range) of wireless health care (and home security) products equipped with this RF module. Compared with an RF module without the proposed DRC, a 10 dB improvement in sensitivity (from −106 to −116 dB) is achieved. Furthermore, RF field test of a wireless health care product (both with and without the proposed DRC in its RF module) shows a more than 100% enhancement in the wireless operation range (from 150 m to more than 300 m) and a 10-dB improvement in adjacent channel selectivity. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2563–2568, 2014