Design of 3.67 GHz RF Power Amplifier Presenters: Akshay Iyer, Logan Woodcock Advisers: Dr. K. Koh, Yahya Mortazavi

Cognitive Radios ●Software defined radio ●Programmed to run by maximizing utility of radio frequency spectrum

Project Goal ●Design and simulate an RF power amplifier that operates between 2 and 4 GHz ●Use ADS software for design and simulation PA Digital Baseband Processor Digital to Analog Converter Modulator Frequency Synthesizer (Oscillator) Antenna (T x ) Receiver (R x )

RF Power Amplifier (PA) ●T x side: Increases the signal amplitude to make it more easily detected Input Matching Network Output Matching Network RF In RF Out Drain Source Voltage MOSFET Transistor Gate Source Voltage Source Load

Metal-Oxide Semiconductor Field- Effect Transistor ●Creates a channel underneath the gate that connects the source and drain terminals ●Channel is created when a large enough voltage is supplied to the gate

Smith Charts Used for Impedance Matching (Max Power Transfer)

Transmission Line Theory Input Impedance Special Cases: Open/Short Circuit Stubs

Amplifier Classes ●A, AB, B, C, F o Phase angles

“Load Line” “Q - Point” - DC Operating Point DC+AC conditions: Vds=Vdd+Vac (time average of Vds must be Vdd) Vac=Vout Id=Iddc+Idac Idac=-Iload=-Vout/RL

Final Schematic ●Consists of two bias networks, two impedance matching networks, and a MOSFET designed by Freescale.

Transistor and Substrate ●Freescale Model MRF8S26060H ●Rogers Substrate

●Class AB o utilizes harmonics ●VDS of 50 V, VGS of 2 V Load Line / FET Curves Results

Power Results ●Max Power Added Efficiency (PAE) of 88%

Bias Networks ●Necessary to bias the transistor to desired level

Load-Pull ●Shows impedance values specific to schematic

Impedance Matching Networks 1. Shunt 2. Series Electrical Length (degrees)

Harmonic Balance Simulation ●Shows the effects of harmonics on output power o Increases efficiency

Scattering - Parameters ●Voltage reflection coefficients o Shows reflected voltage (return loss)

Further Steps in the Process - Layout - EM simulation - Foundry mwrf.com

References G. Saggio, Principles of analog electronics, Edition of book, Boca Raton: Taylor & Francis Group, 2014, p.. B. Razavi, RF microelectronics, 2nd ed., New Delhi: Dorling Kindersley India, 2012, p