In order to achieve the low power goals of PicoRadio, new architectures for the RF receiver must be researched. An important component of the receiver is the low noise amplifier. For our application, the low noise amplifier must provide high gain and adequate noise and linearity while consuming minimal power.
In this research, a design utilizing an inductively degenerated common source amplifier utilizing a RF MEMS FBAR resonator was explored. The FBAR resonator is capable of providing a high Q tank and narrowband filtering. Another advantage of the resonator is that it can ultimately be integrated on-chip. In this architecture, the resonator will be used for tuning the output tank, as well as providing high impedance at resonance in order to generate gain. On-chip spiral inductors are used at the source for input impedance matching, and in parallel with the FBAR resonator at the output to provide DC bias current through the transistors. The gate inductor used to determine the resonant frequency is implemented off-chip. Simulations have shown that a voltage gain exceeding 30 dB can be achieved while using only 500 mA from a 1.2 V supply.
To characterize the performance of the LNA, a prototype was fabricated in a 0.13 mm CMOS process. A PCB board was also made to test the LNA, and results will be available soon.