Asymmetrical intermodulation distortion products due to bias networks in power amplifiers

Study of asymmetrical intermodulation distortion in power amplifiers and its implications for circuit designers has been a growing topic in the last decade. While design guidelines for biasing PAs such that this IMD is reduced have been established, the problem remains as the signal must travel from the power supply to the amplifier on the chip across a distance of copper. This creates a time delay in the signal, which causes changing impedances to be created at the two ends of the copper connection. These effects are often ignored by designers, such that when comparing the operation of the circuit in testing environments versus working in real life conditions, the intermodulation distortion specifications do not act as intended. This project revolved around looking at the change in impedance of the signal as it travels along this distance of copper, and design implications it might have on the asymmetrical intermodulation products created when the circuit operates in real life conditions.