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16] Gielis JA. A generic geometric transformation that unifies a wide range of natural and abstratic shapes. Am J Bot. 2003;90 (3):333-338.[17] Wentworth SM. AbstractThis article presents a microwave wake-up receiver for biotelemetry applications. The circuit is designed using 130 nm CMOS technology and it consists of a passive amplification front end filter, envelope detector and baseband frequency amplifier with variable feedback filtering. The receiver is designed to operate at 7.6 GHz and measured results show that it has a sensitivity of 240 dBm while drawing just 3 lA from a 0.5 V supply. The presented work has the smallest known area and exhibits a competitive tradeoff between DC power, sensitivity, and bit rate. K E Y W O R D S biotelemetry, CMOS, CMOS RF design, low power RFIC design, wakeup receiver

This study reports a frequency-modulated ultra-wideband transmitter optimised for low-power consumption. The chip includes a sub-oscillator tunable from 0.1 to 4 MHz, a radio-frequency oscillator tunable from 3.0 to 4.5 GHz, and an output power amplifier with a matching network. Depending on the channel selected, the measured transmitter consumes between 440 and 640 μW of power to produce −14 dBm continuously to a 50 Ω load. Two power supplies are used to reduce the effect of wasted voltage headroom between circuit blocks. Fabrication is done using the International Business Machines Corporation 130 nm complementary metal-oxide-semiconductor technology on a 1 mm × 1 mm loose die, the circuit occupies 0.2 mm 2 .

This study introduces a frequency modulated ultra-wideband (FM-UWB) receiver optimised for low power and fast start-up. The receiver consists of a front end amplifier converting a frequency modulated signal to an amplitude modulated signal which is applied to an envelope detector. The receiver front end is for 500 MHz channels centred at 3450 and 3950 MHz. The amplifier uses passive gain and four cascaded gain stages to achieve high radio-frequency gain without the need for superregeneration. By simplifying the architecture this way, the front end has a 5 μs wake-up time to enable efficient duty-cycling. The measured front end receives a signal at −68 dBm while consuming 600 μW of power (excluding a test buffer) from a 1 V supply. Fabrication was done using the IBM 130-nm CMOS technology on a 1 mm × 1 mm loose die.