Sensitivity of electrical baseband memory effects to higher-order IF components for high-power LDMOS power amplifiers

Memory effects are complex phenomena that present major design problems in modern high-power microwave power amplifier (PA) design, having a large influence on the suitability of a PA to linearisation through pre-distortion. Presented are detailed modulated measurements that clearly show how baseband electrical memory, introduced by the baseband impedance presented to the device, is by far the most significant contributor to overall observed memory effects in a high-power LDMOS PA design. These investigations are performed on a 20W LDMOS device characterised at 2.1 GHz within a purpose-built, high-power measurement system.