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A wide band radio frequency (RF) root-mean-square (RMS) power detector (PD) is presented in this paper. A CMOS rectifier with unbalanced source-coupled pairs and auxiliary capacitors is utilized to constitute the reverse received signal strength indicator (reverse-RSSI) architecture as proposed power detector with operating frequency from 300 MHz to 10 GHz. The auxiliary capacitors are introduced to improve linearity at high input power dramatically. The power detector can be connected to power amplifier without directional coupler due to the capacitor attenuation array. Simulation results show that the maximum detection power is as high as +30 dBm and dynamic range reaches more than 42 dB with ±1 dB error. The proposed power detector is implemented in a standard 180nm CMOS process with 0.113 mm2 core area. The supply voltage is 3.3 V, and its static power consumption is 0.55 mW.

A novel human body channel (HBC) energy harvesting scheme for body sensor networks (BSNs) is proposed in this paper. Human body channel is utilized innovatively as energy transmission medium to reduce the transmission loss dramatically and eliminate influence of shadow effect. Further, a high sensitivity and efficiency rectifier is presented by introducing an effective threshold compensation circuit. Experimental results of the energy harvesting scheme show that it can supply 2-μW power typically at −5 dBm transmitted power and up to 19.5-μW at +7 dBm transmitted power by 30 cm distance of human body channel. The sensitivity of the proposed rectifier is −22.5 dBm with 1-V output voltage. When offering 5-μA output current, the rectifier can achieve 25.87% efficiency. The rectifier is implemented in a standard 0.18-μm CMOS process and operating frequency is 145 MHz.

This paper presents a 0.5–2GHz RF front-end with Series N-path Filter. With series 8-path filter applied, an ultimate rejection larger than 46 dB with 30 dB out-of-band rejection at 50 MHz offset is achieved. Dynamic power consumption is saved due to small filter switch size compared with parallel structures. Utilizing a tunable narrow band LNA in front of series N-path filter, 3rd harmonic rejection exceeding 54 dB with robust to process variation is realized. These techniques improve the front-end's adjacent and far-end frequency selectivity in RF domain, relaxing mixer's linearity design pressure. Implemented in 65 nm CMOS process, the frontend achieves a NF of 2.6–5.7 dB and maximum gain of 46–60 dB at 0.5–2 GHz, consuming 18–26 mW from 1.2 V voltage supply and occupies an area of 0.56 mm2.