Comparative study based simple analog predistortion design with improved linearization

Analog predistortion (APD) techniques are commonly used for linearization when the baseband information is not available. It is predominantly used in satellite communication because of its small footprint. This article divides the conventional APD structures into two categories, single-path, and multipath APD. It provides a comparative study of these designs, derives the mathematical equations involved with each design, and proposes a new APD method with a small footprint. The proposed design is a single path APD which consists of a π- network with diodes as load impedance in two branches. The equations involved with the proposed design are also derived. A two-tone test with a center frequency of 3.5 GHz and a tone spacing of 10 MHz is performed for this APD with a 10 Watt PA in the simulation environment. The linearization results are measured in terms of carrier-third-order intermodulation ratio (C/I3). PA with the proposed APD shows significant C/I3 improvement as compared to PA without APD.