Jose I. Herranz-Herruzo

Analysis of the coupled chassis-antenna modes in mobile handsets

Due to the development of electronics in the last decade, mobile terminals are becoming smaller and smaller. In the miniaturization process of terminals, the antenna is a critical element. The objective of this paper is to apply the characteristic mode theory, defined by Harrington and Mautz (1971), to identify the modes mentioned in Vainikainen et al. (2002) and consequently improve the design process of the antenna-chassis structure. The theory of characteristic modes brings a clear insight into the physical phenomena taking place in the structure and provides very useful information for the design.

Optimization technique for linearly polarized radial-line slot-array antennas using the multiple sweep method of moments

This paper presents an effective full-wave procedure to optimize linearly polarized radial-line slot-array antennas. The procedure is based on a recursive method for solving large matrix equations known as the multiple sweep method of moments. As a result of this paper, new design suggestions have been introduced which greatly contribute to the performance improvement of this type of antennas. These elements are the arrangement of the slots in concentric ellipses instead of circles and a slight but crucial modification on the usual collocation of the reflection-canceling slots.

Radial-line slot-array antenna loaded with parasitic strips for improved performance

Well-matched linearly polarized radial-line slot-array antennas can be designed using strip-loading techniques, avoiding the use of cancelling slots and therefore obtaining high levels of polarization purity and eliminating undesired backward radiation.

Compact switchable RHCP/LHCP mobile Ka-band antenna

This document describes a new concept of a mobile Ka band antenna for satellite communications. The antenna exhibits low profile and can cope with the stringent specification of polarization switching required in the handover from cell to cell. Transmit performance is discussed in detail and compared with an equivalent reflector antenna.

Rectangular waveguide with low metallic losses on side walls at THz

A rectangular waveguide for low-loss transmission at THz frequencies is proposed. The waveguide is based on the reflection of the fundamental mode on the side walls. By adding a stratified medium, a low impedance condition is obtained in the inner wall. Attenuation in side walls is eliminated.

New topologies of radial-line slot-dipole array antennas

This paper proposes new topologies of linearly polarized radial-line slot-array antennas (LP-RLSA) which uses slot-dipole pairs as radiating elements. Firstly, the basic design of the antenna with cancelling slots is considered and its benefits and drawbacks are highlighted. The evolution of this configuration leads to more convenient arrangements of the radiating and cancelling elements. Finally, a LP-RLSA composed of doubled rings demonstrates to be the most suitable topology for this kind of antennas.

Pattern reconfigurable Ka-band slot-array antenna using RF-MEMS †

Cylindrical measurement systems require two sweeps around the antenna under test (AUT). One sweep is a translation movement (vertical) and the other one a rotation movement (roll). Whereas the rotation movement is normally done by the AUT, the translation movement is commonly carried out by the probe [1]. This translation can be avoided by using a probe with a reconfigurable pattern. Thus, instead of moving the probe physically, the probe pattern is electronically swept from one side to the other side of the probe [2]. By doing so the vertical scanning is performed faster.

A discussion on the characteristic mode theory limitations and its improvement for the effective modeling of antennas and arrays

The objective of this work is to present a new method for accelerating MoM computation in antenna arrays. This method is based on a new class of frequency independent entire domain basis functions that are directly obtained from the characteristic modes defined by Harrington and Mautz (IEEE Trans. Antennas Propagat., vol. AP-19, no. 2, pp. 622-628, 1971).

Practical Derivation of Slot Equivalent Admittance in Periodic Waveguides

This communication describes a procedure for obtaining the equivalent-admittance representation of a slot in a waveguide. The approach is general, but it is particularly interesting for periodic waveguides, because it does not require knowing the Greens function of the wave guides or properly defining the ports in such waveguides. The procedure is demonstrated on a well-known rectangular waveguide. It is later applied to a periodic waveguide and used to design a small array. Measurements of the array performance are shown so as to validate the approach.

V-band single-layer slot array fed by ridge gap waveguide

A compact feeding structure for slot arrays is proposed in the context of so-called ridge gap waveguides. Slots are fed through a corporate feed network in ridge gap waveguide technology and backed by coaxial cavities. Coaxial cavities are very easy to integrate within the bed of nails hosting the ridge and lead to very compact 2 χ 2 basic radiating cell.