Affan A. Baba

Two-level optimization of a stepped dielectric superstrate to increase gain of a resonant cavity antenna

In this paper, customized full-wave optimization of resonant cavity antennas (RCAs) is presented. The objective was to design RCAs with a high directivity-bandwidth product (DPB) for medium-to-high-gain space-limited applications. For this, a speed-constrained particle-swarm optimization (SMPSO) algorithm was implemented in MATLAB, which iteratively interacted with the 3D full-wave simulator of CST Microwave Studio during the optimization process. The optimization resulted in a stepped dielectric superstrate, which when used in an RCA demonstrated a measured broadside directivity of 20.7 dBi with an extremely large directivity bandwidth of greater than 50%.

On the use of external MATLAB-based optimization with full-wave simulation to design resonant cavity antennas (Special session)

In this paper, a method to combine MATLAB-based optimization with a 3D electromagnetic simulator is described. The work-flow is presented using five main files (.m, .text, .bas, .sig and .rd1), which are required to establish the connection between the two software systems. Speed constrained particle swarm optimization (SMPSO) algorithm was implemented in MATLAB, which utilized the transient 3D simulator of CST Microwave Studio to carry out iterative full-wave analyses during the optimization process. As a design example, this customized optimization method was then employed to maximize the directivity-bandwidth product (DBP) of a mono-slab resonant cavity antenna (RCA). This optimization yielded a compact RCA, with a peak directivity of 21dBi and an extremely large directivity-bandwdith of 56%. The DBP of this optimized RCA is around 6500 and its total area is only 5.6λ20.

Preliminary results of an array of resonant cavity antennas at 60 GHz

In this paper, preliminary results of an array of resonant cavity antennas (RCAs) to operate at 60 GHz are presented. Each RCA in the array has a two-layers all-dielectric superstructure with permittivity variation in axial direction. The single RCA element exhibits a peak directivity of 16.6 dBi and its 3dB directivity bandwidth covers the entire unlicensed 60 GHz band from 59 GHz to 67 GHz. The RCA array has a peak directivity of 22.8 dBi with a 3dB directivity bandwidth of 33%. The inter-element spacing between the array elements is optimized to achieve the best performance in terms of peak directivity and radiation bandwidth. The total area of the RCA array is 3.8λ0 × 3.8λ0.

A simple electromagnetic bandgap resonator antenna for 60 GHz wireless applications

In this paper, a simple wideband electromagnetic bandgap (EBG) resonator antenna (ERA) with an all-dielectric superstructure is presented to operate at 60 GHz. The antenna superstructure consists of two circular dielectric slabs with different relative permittivity values. A waveguide-fed slot antenna is used to excite the antennas cavity and is placed about half a wavelength from the superstructure. The single ERA element exhibits a peak directivity of 16.6 dBi with a directivity bandwidth of 35%. In addition to this, the antennas directivity remains greater than 14.3 dBi over the entire unlicensed 60 GHz wireless band from 59 GHz to 67 GHz. The feed antenna is well matched over the frequency band and the overall ERA has total footprint of only 1.5λ02.

Wideband single-feed highly directive resonant cavity antennas with all-dielectric superstructures

In this paper, we review two new classes of superstructures for single-feed wideband resonant cavity antennas (RCAs). Both the superstructures are composed of only dielectric materials and have non-uniform permittivity in either the axial direction, i.e., perpendicular to the antenna axis, or in the transverse plane. These superstructures not only make the resulting RCAs significantly wideband, along with their excellent directive characteristics, but also add compactness to the overall design. The presented RCAs have the advantages of simple configurations, low-cost manufacturing, polarization versatility, and controlled structural sensitivity for extension to millimeter wave designs.

Recent advances in electromagnetic band gap resonator antennas

This paper presents recent advances related to electromagnetic band gap (EBG) resonator antennas (ERAs). In particular, we briefly review three new classes of ERAs (a) ERAs having extremely small footprints and superstructures with axial permittivity variation (APV), (b) ERAs with dielectric superstructures having transverse permittivity gradients (STPG), and (c) ERAs with phase-correcting structures (PCS). These classes present significant performance improvements compared to classical designs. State-of-the-art performance figures for each of these classes are presented after summarizing the key developments in this area.