No abstract

We demonstrate the beneficial effects of introducing glide symmetry in a two-dimensional periodic structure. Specifically, we investigate dielectric parallel plate waveguides periodically loaded with Jerusalem cross slots in three configurations: conventional, mirror- and glide-symmetric. Out of these three configurations, it is demonstrated that the glide-symmetric structure is the least dispersive and has the most isotropic response. Furthermore, the glide-symmetric structure provides the highest effective refractive index, which enables the realization of a broader range of electromagnetic devices. To illustrate the potential of this glide-symmetric unit cell, a Maxwell fish-eye lens is designed to operate at 5 GHz. The lens is manufactured in printed circuit board technology. Simulations and measurements are in good agreement and a measured peak transmission coefficient of −0.5 dB is achieved.

Quasi-optical beamformers provide attractive properties for antenna applications at millimetre-wave frequencies. Antennas implemented with these beamformers have demonstrated wide angle switching of directive beams, making them suitable as base station antennas for future communication networks. For these applications, it is essential to ensure a high beam crossover gain to provide a robust service to end users within the steering range. Here, we propose a geodesic generalized Luneburg lens antenna operating from 57 to 67 GHz that provides increased crossover gain compared to previously reported geodesic Luneburg lens antennas. The focal curve of the generalized Luneburg lens can be displaced from the beamformer, allowing for a higher angular resolution in the placement of the feed array along the focal curve. The lens is fed with 21 ridge waveguides with an angular separation of 5.1 degrees, thus providing beam steering in a 102-degree range. The peak realized gain varies from 19 to 21 dBi throughout the steering and frequency ranges and the beam crossover gain is roughly 3 dB below the peak gain. The simulations are experimentally validated.