ABSTRACT
This chapter provides an overview of the subject of single frequency amplitude modulated (AM) analog- or digital-capable omnidirectional or directional antenna system design. It presents a typical phasing system topology showing the power division, calculated equivalent input resistance values, and phase budget. Modern tools such as the Method of Moments (MOM) and nodal circuit analysis (Spice and its derivatives) programs permit effective matching and phasing networks to be routinely designed. The network and tower characteristics such as effective electrical height and mutual coupling can be accurately characterized, especially when field measurements are incorporated into the model to calibrate and fine tune the antenna model. To achieve the best end-to-end performance of an AM transmission system from the output of the combined radiofrequency (RF) amplifiers to the wideband AM analog or digital receiver, a total RF system design approach is required.
