The term photonic crystals appears because of the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures. During the recent years the investigation of one-, two-and three-dimensional periodic structures has attracted a widespread attention of the world optics community because of great potentiality of such structures in advanced applied optical fields. The interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.

http://ieeexplore.ieee.org/iel5/6354/16969/00781867.pdf

Photonic crystals

Electromagnetic Metamaterials: Transmission Line Theory and Microwave Applications. By Christophe Caloz and Tatsuo Itoh.

Space-Time Block Coding for Wireless Communications

In general, Micropower Impulse Radar (MIR) depends on Ultra-Wideband (UWB) transmission systems. UWB technology can supply innovative new systems and products that have an obvious value for radar and communications uses. Important applications include bridge-deck inspection systems, ground penetrating radar, mine detection, and precise distance resolution for such things as liquid level measurement. Most of these UWB inspection and measurement methods have some unique qualities, which need to be pursued. Therefore, in considering changes to Part 15 the FCC needs to take into account the unique features of UWB technology. MIR is applicable to two general types of UWB systems: radar systems and communications systems. Currently LLNL and its licensees are focusing on radar or radar type systems. LLNL is evaluating MIR for specialized communication systems. MIR is a relatively low power technology. Therefore, MIR systems seem to have a low potential for causing harmful interference to other users of the spectrum since the transmitted signal is spread over a wide bandwidth, which results in a relatively low spectral power density.

/pdf/response-to-fcc-98-208-notice-of-inquiry-in-the-matter-of-3attixctl7.pdf

Response to FCC 98-208 notice of inquiry in the matter of revision of part 15 of the commission's rules regarding ultra-wideband transmission systems

We present a flexible, compact antenna system intended for telemedicine applications. The design is based on an M-shaped printed monopole antenna operating in the Industrial, Scientific, and Medical (ISM) 2.45 GHz band integrated with a miniaturized slotted Jerusalem Cross (JC) Artificial Magnetic Conductor (AMC) ground plane. The AMC ground plane is utilized to isolate the user's body from undesired electromagnetic radiation in addition to minimizing the antenna's impedance mismatch caused by the proximity to human tissues. Specific Absorption Rate (SAR) is analyzed using a numerical human body model (HUGO) to assess the feasibility of the proposed design. The antenna expresses 18% impedance bandwidth; moreover, the inclusion of the AMC ground plane increases the front to back ratio by 8 dB, provides 3.7 dB increase in gain, in addition to 64% reduction in SAR. Experimental and numerical results show that the radiation characteristics, impedance matching, and SAR values of the proposed design are significantly improved compared to conventional monopole and dipole antennas. Furthermore, it offers a compact and flexible solution which makes it a good candidate for the wearable telemedicine application.

Flexible and Compact AMC Based Antenna for Telemedicine Applications

This paper is analyzed the reduction of specific absorption rate (SAR) with metamaterials attachment. The SAR reduction methodology is discussed and the effects of attaching location, distance, and size of metamaterials, on the SAR reduction are explored. Metamaterials have achieved a 57.75 % reduction of the initial SAR value for the case of 10 gm SAR. Index Terms – antenna, human head model, lossy-Drude model, metamaterials, specific absorption rate (SAR).

Evaluation of Specific Absorption Rate (SAR) Reduction for PIFA antenna Using Metamaterials

In this paper, a novel multiple slot microstrip patch antenna with enhanced bandwidth is presented. The design adopts contemporary techniques namely; probe feeding, inverted patch structure and multiple slotted patch. The composite effect of integrating these techniques and by introducing the novel multiple shaped patch, offer a low profile, wide bandwidth, high gain and compact antenna element. The proposed patch has a compact dimension of 0.707 lambda0 times 0.354 lambda0 (where lambda0 is the guided wavelength of the center operation frequency). With the proposed concept, an antenna prototype is simulated and analyzed. The proposed antenna achieves a fractional bandwidth of 27.15% (1.91 to 2.51 GHz) at 10 dB return loss while maintaining a maximum gain of 10.5 dBi. The design is suitable for array applications especially for base station.

Analysis of broadband slotted microstrip patch antenna

The design and prototyping of a new double L-shaped patch antenna on substrate of available low cost polymer resin composite material is presented The designed microstrip line fed compact antenna consists of a planar double L-shaped slotted radiating patch, 16 mm thick substrate and ground plane The proposed small antenna was designed and analyzed using a finite-element method-based, commercially available, high frequency structure simulator, and fabricated on a printed circuit board The measured −10 dB return loss bandwidths were 220 MHz and 650 MHz at 485 GHz and 810 GHz center frequencies The corresponding symmetric and almost steady radiation patterns have peak gains of 76 dBi and 41 dBi, making the proposed antenna suitable for C and × band wireless applications, especially for WLANs, mobiles and satellites The radiation efficiency, input impedance and current distribution of the proposed antenna were also analyzed

A new double L-shaped multiband patch antenna on a polymer resin material substrate

https://cyberleninka.org/article/n/1133805.pdf

Dual Band X Shape Microstrip Patch Antenna for Satellite Applications

The aim of this paper is to evaluate the specific absorption rate (SAR) reduction in a muscle cube by using metamaterial. To evaluate the SAR in a realistic anatomically based model of the muscle cube, the finite-difference time-domain (FDTD) method has been utilized. The effective medium parameter is obtained to be negative at 900 MHz and 1800 MHz band by designing structural parameter of split ring resonators. The reduction is about 44.73% for 900 MHz, and about 48.27% for 1800 MHz was observed in this paper.

Norbahiah Misran

Papers

Evaluation of Specific Absorption Rate (SAR) Reduction for PIFA antenna Using Metamaterials

Analysis of broadband slotted microstrip patch antenna

A new double L-shaped multiband patch antenna on a polymer resin material substrate

Dual Band X Shape Microstrip Patch Antenna for Satellite Applications

SAR reduction in a muscle cube with metamaterial attachment