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A novel single-layer, microstrip-toslotline transition technique for coupling a circularly polarized annular-ring slot antenna in the UHF band is presented. In the proposed design, circular polarization is generated using a proper asymmetry within the annular-ring slot structure and feeding the annular-ring slot using a slotline feed at 135° from the asymmetry. The direct slotline feed is used which is coupled to a 50-? microstrip line on the opposite side of the substrate. The asymmetry in the proposed design is a meandered-slot section and the proposed CP design is achieved by the two orthogonal linear modes of the annular-ring slot. Simulated and measured results indicate that the proposed structure can achieve good CP radiation performances, and an impedance bandwidth and a 3-dB axial-ratio bandwidth obtained for the design are about 17.6% and 3.72%, respectively.

In this paper, a specialized genetic algorithm (GA) combined with Rayleigh-Ritz method is used to obtain the dimensions of elliptical dielectric resonators (EDRs) for dual-band, wide-band, or circular polarization (CP) operation. Slot-coupled elliptical dielectric resonator antennas (EDRA’s) and their characteristics are investigated. Parametric studies are presented to study the dependence of the return loss on the slot parameters. These parametric studies are used to optimize the slot dimensions and its position to excite given desired modes.

This paper represents a high-gain, single resonance microstrip patch antenna which operates at 14.70 GHz.

A sequential phase (SP) feed array antenna circularly polarized (CP) with 2×2 patch array is presented. The feeding network consist of two piece of circle that are filled with rectangular lines and have four arms that make 900 phase difference for the corner truncated elements which are connected to the feeding network. The combination of circle and rectangular lines reduces the size of the feeding network and thus, the overall size of the antenna with good characteristics to prove the antenna performance, the prototype antennas built and the results come in the form of: the measured 10 dB impedance bandwidth is 0.5 GHz (3.45 - 3.95 GHz), and the measured 3-dB AR bandwidth is 0.3 GHz (3.45 - 3.75 GHz).

Attention to dielectric resonator antennas (DRA) has been increasing because of their small size, bandwidth, high radiation efficiency [1] and ease of excitation. Attention was also toward linearly polarized DRA [2-3] and wideband antennas [4-5]. Circularly polarized DRA has been studied experimentally in a sub-array environment. The circular polarization is excited by a cross-slot excitation [6-8] or by designing a crossed-shape dielectric resonator [7]. All these studies have been performed experimentally to excite two orthogonal modes with 90 degree phase shift between them. If single feed is required, a perturbation for the geometry can be used to achieve that. However, always such technique provides very small circular polarization bandwidth. If such antenna is used in a sub-array with a sequential feeding mechanism of each two elements or four elements sub-array a much wider bandwidth for the circular polarization can be achieved. Here, we design a circularly polarized elliptic dielectric resonator with single probe feeding. The probe position and parameters are used to match the antenna and to excite the circular polarizations. The analysis is performed numerically using WIPL-D [9].

A miniature dual-band GPS antenna is proposed for compact GPS arrays or portable GPS devices. Slots are cut on the patch to further reduce the antenna size to one inch (y/10 at the L2 band). A single-fed quadrature-phase splitter is designed to reduce the array electronics. Design concepts and procedures are presented along with performance assessment using FEKO.