This paper describes how the performance of wearable textile antennas is affected on the antenna bending. Here, we will focus on the resonance frequency fluctuation and input-match bandwidth variation due to the antenna bending. The results are given for three different antennas, namely, a conventional patch, EBG, and dual-band U-slot antennas.

Textile antennas: Effects of antenna bending on input matching and impedance bandwidth

How the performance of wearable textile antennas is affected on the antenna bending is described herein. The authors focus on the resonance frequency fluctuation and input-match bandwidth variation due to the antenna bending. The results are given for three different antennas, namely, a conventional patch, EBG, and dual-band U-slot antennas

Textile antennas: effects of antenna bending on input matching and impedance bandwidth

Textile Antennas: Effects of Antenna Bending on Input Matching and Impedance Bandwidth

How the performance of wearable textile antennas is affected on the antenna bending is described herein. We will focus on the resonance frequency fluctuation and input-match bandwidth variation due to the antenna bending. The results are given for three different antennas, namely, a conventional patch, ERG, and dual-band U-slot antennas.

http://ieeexplore.ieee.org/iel5/62/4145065/04145071.pdf

Textile Antennas: Effects of Antenna Bending on Input Matching

A compact of a reconfigurable rectangular microstrip slot patch antenna of operating frequencies in the range of (2–6) GHz is proposed for Wireless Local Area Network (WLAN) applications. It has one port excited with microstrip line feed mechanism. The proposed antenna consists of a single layer patch antenna with two parallel slots designed that can be controlled via two PIN diode switches. Two parallel slots are incorporated to perturb the surface current path, introducing local inductive effect that is responsible for the excitation of the second resonant mode. By adjusting the status of the switches state either on or off mode in simultaneously, the resonance frequencies can be varied, thus achieving frequency reconfigurable. A comprehensive parametric study has been carried out to understand the effects of various dimensional parameters (slots and PIN diode switches) and to optimize the performance of the antenna. This antenna is capable to achieve return loss less than −10dB and VSWR≤2 in multiband frequencies at 2.4GHz and 5.8GHz when both switches are ON mode while only in 2.4GHz can be achieved when both switches are OFF mode. The designed antennas have been also fabricate onto FR-4 and measured to compare the real results of return loss (S 11 ) and voltage standing wave ratio (VSWR) with those obtained from the simulations. The proposed antenna is very promising for various modern communication applications.

A design of reconfigurable rectangular microstrip slot patch antennas

The advantages of antennas that can resemble the shape of the body to which they are attached are obvious. However, electromagnetic modeling of such unusually shaped antennas can be difficult. In this paper, the commercially available software SolidWorks/spl trade/ is used for accurately drawing complex shapes in conjunction with the electromagnetic software FEKO/spl trade/ to model the EM behavior of conformal antennas. The application of SolidWorks and custom-written software allows all the required information that forms the analyzed structure to be automatically inserted into FEKO, and gives the user complete control over the antenna being modeled. This approach is illustrated by a number of simulation examples of single, wideband, multi-band planar and curved patch antennas.

Electromagnetic modeling of conformal wideband and multi-band patch antennas by bridging a solid-object modeler with MoM software

In modern living, there is enormous emphasis on any commercial product to not only perform, but to look good as well. In some cases, the antenna is often perceived as being ugly in the eyes of the consumer, particularly if it protrudes from the device or object that features a curved surface. A typical example is the antennas located on a future modern vehicle to access the future multimedia services (T. Talty et al., Ant. and Propag. Soc., IEEE Int. Symp., vol. 1, pp. 430-433, 2001). In these applications, antennas have to conform to a spherical or pseudo spherical surface to mask their presence. These types of surfaces present problems when microstrip patch antennas have to conform to them. Typically, microstrip antennas are designed for a planar surface. Conforming them to a spherical surface introduces distortions to their shape. This paper outlines a method based on experimental data of predicting how a simple planar wideband L-probe fed patch and its ground plane will distort when spherically conformed. A method of predicting the new design of the spherically conformed patch antennas is given so that its performance can be modelled accurately.

Modelling the distortions to manufacture spherical conformal microstrip antennas

This paper has described the theoretical design of a wideband circular L-probe patch antenna covering the ISM band of 2.4GHz. To increase the effective radiation area, the antenna is spherically conformed. To overcome the dielectric material cracking in the commercial microstrip due to the spherical distortions, an air dielectric is assumed, making the design of the antenna very simple and inexpensive. A grid pattern is overlayed on a planar 1.6mm thick commercial grade piece of aluminium cut to a circle with a radius of 100mm. This material is spherically conformed and the distortions measured to become the basis of the spherical conformal ground plane and the benchmark of the conformal element design. The different S/sub 11/ responses of the antenna are shown for different values of the element radius. The radiation pattern for the conformal antenna design shows an increase in the effective radiation area when compared to the flat antenna design. The conformal design also has a response similar to a /spl lambda//4 monopole with a maximum gain of 6dB.

The effects of spherical conformity on a wideband L-probe circular patch antenna

Two patch antennas have been modelled when they are conformed to the shape of a sphere using a technique for drawing unusual shaped antennas and commercially available MoM electromagnetic modelling software. First, a simple L-band printed circular patch antenna on a square groundplane was modelled with the theoretical results showing good agreement with those obtained experimentally. Next, a circular patch antenna, conforming to a sphere, has been studied. Theoretical input reflection coefficient and polar radiation plots have been produced showing the effect of curvature. Next, an "E" shaped PIFA triple band antenna etched on a thin piece of copper foil designed for the GSM and PCS frequencies of 900, 1800 and 1900 MHz has been modelled on a spherical host for differing radii, producing reasonable results. The S11 and polar radiation plots have shown very little influence of curvature, perhaps due to the small distance of the antenna from the ground plane.

Modelling the effect of 3D conformity on single and multi-band patch antennas

What do we do when there is a need to model antennas and ground planes that have a geometry that is not planar? The accurate representation of our geometry can make a significant difference in the results, especially at higher frequencies. This paper describes how some powerful computer-aided design (CAD) tools can be developed to represent difficult non-planar antenna geometries that cannot always be drawn using the commercial EM modeling packages. These CAD tools not only become very useful design tools, but are also essential when it comes to designing the complicated geometry associated with spherical conformal antennas.

B.R. Piper

Papers

Electromagnetic modeling of conformal wideband and multi-band patch antennas by bridging a solid-object modeler with MoM software

Modelling the distortions to manufacture spherical conformal microstrip antennas

The effects of spherical conformity on a wideband L-probe circular patch antenna

Modelling the effect of 3D conformity on single and multi-band patch antennas

The Design of Spherical Conformal Antennas Using Customized Techniques Based on NURBS