This document provides updates to IEEE Std 802.16's MIB for the MAC, PHY and asso- ciated management procedures in order to accommodate recent extensions to the standard.

IEEE Standard for Local and Metropolitan Area Networks Part 16: Air Interface for Fixed Broadband Wireless Access Systems Draft Amendment: Management Information Base Extensions

Resonance conditions for a substrate-superstrate printed antenna geometry which allow for large antenna gain are presented. Asymptotic formulas for gain, beamwidth, and bandwidth are given, and the bandwidth limitation of the method is discussed. The method is extended to produce narrow patterns about the horizon, and directive patterns at two different angles.

Gain enhancement methods for printed circuit antennas

This review of array antennas highlights those elements of theory and hardware that are a part of the present rapid technological growth. The growth and change in array antennas include increased emphasis on "special-purpose" array techniques such as conformal and printed circuit arrays, wide angle scanning arrays, techniques for limited sector coverage, and antennas with dramatically increased pattern control features such as low sidelobe, adaptively controlled patterns. These new topics have substantially replaced large radar arrays in the literature and constitute a major change in the technology. The paper presents a tutorial review of theoretical developments emphasizing techniques appropriate to finite arrays, but indicating parallel developments in infinite array theory, which has become the useful tool for analysis of large arrays. A brief review of the theory of ideal arrays is followed by a generalized formulation of array theory including mutual coupling effects, and is appropriate to finite or infinite arrays of arbitrary wire elements or apertures in the presence of a conducting ground screen. Some results of array tolerance theory are summarized from the literature and retained as reference throughout discussions of array component requirements and device tolerance for low sidelobe arrays. Examples from present technology include conformal and hemispherical coverage arrays, lightweight printed circuit arrays, systems for use with reflectors and lenses in limited sector coverage applications, and wide-band array techniques.

Phased array theory and technology

Wearable antennas have gained much attention in recent years due to their attractive features and possibilities in enabling lightweight, flexible, low cost, and portable wireless communication and sensing. Such antennas need to be conformal when used on different parts of the human body, thus need to be implemented using flexible materials and designed in a low profile structure. Ultimately, these antennas need to be capable of operating with minimum degradation in proximity to the human body. Such requirements render the design of wearable antennas challenging, especially when considering aspects such as their size compactness, effects of structural deformation and coupling to the body, and fabrication complexity and accuracy. Despite slight variations in severity according to applications, most of these issues exist in the context of body-worn implementation. This review aims to present different challenges and issues in designing wearable antennas, their material selection, and fabrication techniques. More importantly, recent innovative methods in back radiations reduction techniques, circular polarization (CP) generation methods, dual polarization techniques, and providing additional robustness against environmental effects are first presented. This is followed by a discussion of innovative features and their respective methods in alleviating these issues recently proposed by the scientific community researching in this field.

/pdf/wearable-antennas-a-review-of-materials-structures-and-5bzxx4cp70.pdf

Wearable Antennas: A Review of Materials, Structures, and Innovative Features for Autonomous Communication and Sensing

The simultaneous improvement in radiation and scattering performance of an antenna is normally considered as contradictory. In this paper, wideband gain enhancement and radar cross section (RCS) reduction of Fabry–Perot (FP) resonator antenna are both achieved by using chessboard arranged metamaterial superstrate (CAMS). The CAMS is formed by two kinds of frequency-selective surfaces. The upper surface of CAMS is designed to reduce RCS based on the phase cancellation principle, and the bottom surface is used to enhance antenna gain on the basis of FP resonator cavity theory. Both simulation and measured results indicate that compared with primary antenna, the gain of the proposed FP resonator antenna is enhanced by 4.9 dB at 10.8 GHz and the 3 dB gain bandwidth is from 9.4 to 11.1 GHz (16.58%). Meanwhile, the RCS of the proposed FP resonator antenna is reduced from 8 to 18 GHz, with peak reduction of 39.4 dB. The 10 dB RCS reduction is obtained almost from 9.6 to 16.9 GHz (55.09%) for arbitrary polarizations. Moreover, the in-band RCS is greatly reduced, owing to the combined effect of CAMS and FP resonator cavity.

Wideband Gain Enhancement and RCS Reduction of Fabry–Perot Resonator Antenna With Chessboard Arranged Metamaterial Superstrate

a simple ultra-wideband antenna with monopolelike radiation pattern is presented in this paper. The structure of this low profile antenna with height of the 7 mm (0.65 ; min ) is based on annular-ring circular patch. To improve the antenna’s bandwidth, the main annular-ring circular patch is loaded with two concentric rings and two rectangular slots. The result shows the antenna achieves a 10 dB return loss bandwidth from 2.85 GHz to 8.6 GHz. The monopole-like radiation pattern is maintained throughout the frequency bands by combining four propagation modes of TM 01 , TM 02 , and TM 03 .

/pdf/a-low-profile-uwb-circular-patch-antenna-with-monopole-like-41qlw6vxsx.pdf

A Low Profile, UWB Circular Patch Antenna with Monopole-Like Radiation Characteristics

Wideband arrays of high aperture efficiency EBG resonator antennas are proposed and studied in this paper. The performance of these arrays is characterized based on their directivity and the 3dB bandwidth they can provide. Two configurations of ERAs made out of the same superstructure are compared: (a) an array of high aperture efficiency ERAs and (b) a single ERA with multi-point excitation. It is shown that although the footprint of both the configurations is the same, the array is not only more directive but also presents a significantly higher bandwidth potential. Numerical results are presented to demonstrate a configuration approaching a peak directivity of 21.3 dBi over a 3dB bandwidth of 37%.

Arrays of high aperture efficiency wideband EBG resonator antennas

In this paper the morphology of the polydimethylsiloxane (PDMS)-flexible-conductive-mesh composite has been studied to evaluate its suitability in the realization of robust, flexible, transparent, wearable antennas that can withstand multiple bending operations. We have utilized conductive mesh made out of VeilShield from Less EMF which has about 70% light transmittance and is highly flexible. On the other hand, PDMS is a highly flexible and optically transparent polymer. Uncured PDMS is in liquid form and upon curing it transforms to a robust flexible substrate and forms a strong bonding with the conductive mesh, VeilShield. We have examined the composite through Scanning Electron Microscope (SEM) images during and after multiple bending operations. Later, we have designed a simple patch antenna operating at 2.45 GHz band using our selected materials. For performance evaluation the antenna is tested in both free space and under bent conditions and the results are presented in this paper.

Robustness Analysis of the Polymer-Conductive-Mesh Composite for the Realization of Transparent and Flexible Wearable Antennas

This paper presents a planar, low-profile and low-cost resonant cavity antenna for satellite reception applications. The antenna has a total height of only 0.468X at 12GHz, and consists of a single layer metallo-dielectric superstrate. It is designed to cover the entire ITU Region 3 downlink band for Direct Broadcast Satellite (DBS) services. Numerical results demonstrate a peak directivity of 19.3 dBi with only one tile, which is 10cm × 10cm. Several tiles can be cascaded to increase antenna gain and directivity further.

Planar high-gain antennas for direct broadcast satellite reception

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 antenna's 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 antenna's 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 1.5λ20.

Raheel M. Hashmi

Papers

A Low Profile, UWB Circular Patch Antenna with Monopole-Like Radiation Characteristics

Arrays of high aperture efficiency wideband EBG resonator antennas

Robustness Analysis of the Polymer-Conductive-Mesh Composite for the Realization of Transparent and Flexible Wearable Antennas

Planar high-gain antennas for direct broadcast satellite reception

A simple electromagnetic bandgap resonator antenna for 60 GHz wireless applications