D. Roscoe

EHF aperture-coupled microstrip antenna development

Aperture-coupled microstrip antennas have been developed for operation in the millimeter wave region. A combination of patch dimensions and aperture size determines the antennas resonating frequency. The measured return loss indicated an achievable bandwidth of 1.2% for a VSWR of less than 2:1. The measured radiation patterns at 45 GHz display the expected characteristics of microstrip patch antennas. Measurement of several antennas confirms the repeatability of the results.

Pattern reconfiguration with an active integrated antenna

An active integrated antenna element has previously been developed and presented [1]. The general configuration of this antenna is given in Fig. 1a) while the fabricated prototype antenna is given in Fig. 1b). This antenna utilizes active devices as part of the radiating structure, thus allowing both current amplitude and phase to be controlled along the antenna structure. This provides a control mechanism for antenna performance which is not possible with passive antennas. A unique feature of this antenna in its present topology is that the radiated pattern may be reconfigured with the integrated active devices. This may be achieved by altering the current phase distribution along the antenna structure. The fabricated antenna has been demonstrated to operate in its first order broadside mode and a higher order mode where conical shaped patterns are generated.