Frequency Scanned and Leaky-Wave Linear Slot Arrays

Abstract

In this chapter the scrutiny of the travelling wave array antenna performed in Chap. 7 is used as a ‘launch-pad’ to address and explore frequency scanning techniques for compact arrays. In particular, methods used to enhance scan rates for slotted waveguide array antennas without sacrificing antenna gain and sidelobe levels are explored. The focus on scanned slotted waveguide arrays naturally lead to a need to address the rather different electromagnetic characteristics of the related leaky-wave antenna. This is an antenna type which is becoming increasingly attractive to developments in compact and mobile communications systems, and in remote sensing roles, particularly at millimetre wave and higher frequencies. Physically the travelling wave array described in the previous chapter is not too dissimilar to this important, but electromagnetically quite distinct leaky array structure. We shall explore here the essence of the divergence, in electromagnetic properties, between these superficially rather similar antennas.