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

An ultra-compact broadband antenna easily integrable on portable devices is presented. The antenna is composed of a printed rectangular radiating element and a C-strip printed as the ground plane on the other side. The overall antenna occupies a compact area of 56.5 × 2 × 0.5 mm , yet generating two resonant modes to form 39% (850MHz) wide impedance bandwidth from 1.75 to 2.6GHz with stable omni-directional radiation pattern with low cross-polarization.

/pdf/ultra-compact-wideband-antenna-for-portable-device-4v901yhirb.pdf

Ultra-compact wideband antenna for portable device applications

This paper presents a printed multi-standard wireless antenna fabricated from a cost effective composite material to cover GPS (1575 MHz), GSM 1800, GSM 1900, WLAN (2400 MHz), LTE band 40 (23–24 GHz), WiMAX (3600 MHz) and WLAN (51–535 GHz) frequency bands The reported antenna is incorporated with two distinct monopole radiators with a meanderline-type ground plane The wireless mobile antenna can be conveniently simulated with the commercially available EM simulation software (CST Microwave Studio) using the finite-difference time-domain (FDTD) method A parametric analysis of the antenna geometry is demonstrated and the specific absorption rate (SAR) is also analyzed with a human-head model

/pdf/composite-material-printed-antenna-for-a-multi-standard-3dq2kxwfsw.pdf

Composite-material printed antenna for a multi-standard wireless application

i in terms of bit error rate (BER). Simulation results indicate that the proposed method considerably improves the system performance and significantly reduces the complexity caused by matrix inversion. The performance and complexity of the proposed method clearly outperforms the conventional LS channel estimation method and proves itself a smart solution for MIMO channel estimation.

Performance and Complexity Improvement of Least Squares Channel Estimation in MIMO Systems

/pdf/pattern-reconfigurable-dielectric-resonator-antenna-using-1hryxzzu8t.pdf

Pattern reconfigurable dielectric resonator antenna using parasitic feed elements for lte femtocell base stations

Abstract In this paper, proposes a microwave brain imaging system to detect brain tumors using a metamaterial (MTM) loaded three-dimensional (3D) stacked wideband antenna array. The antenna is comprised of metamaterial-loaded with three substrate layers, including two air gaps. One 1 × 4 MTM array element is used in the top layer and middle layer, and one 3 × 2 MTM array element is used in the bottom layer. The MTM array elements in layers are utilized to enhance the performance concerning antenna’s efficiency, bandwidth, realized gain, radiation directionality in free space and near the head model. The antenna is fabricated on cost-effective Rogers RT5880 and RO4350B substrate, and the optimized dimension of the antenna is 50 × 40 × 8.66 mm 3 . The measured results show that the antenna has a fractional bandwidth of 79.20% (1.37–3.16 GHz), 93% radiation efficiency, 98% high fidelity factor, 6.67 dBi gain, and adequate field penetration in the head tissue with a maximum of 0.0018 W/kg specific absorption rate. In addition, a 3D realistic tissue-mimicking head phantom is fabricated and measured to verify the performance of the antenna. Later, a nine-antenna array-based microwave brain imaging (MBI) system is implemented and investigated by using phantom model. After that, the scattering parameters are collected, analyzed, and then processed by the Iteratively Corrected delay-multiply-and-sum algorithm to detect and reconstruct the brain tumor images. The imaging results demonstrated that the implemented MBI system can successfully detect the target benign and malignant tumors with their locations inside the brain. 

https://www.nature.com/articles/s41598-022-20944-8.pdf

Norbahiah Misran

Papers

Ultra-compact wideband antenna for portable device applications

Composite-material printed antenna for a multi-standard wireless application

Performance and Complexity Improvement of Least Squares Channel Estimation in MIMO Systems

Pattern reconfigurable dielectric resonator antenna using parasitic feed elements for lte femtocell base stations

Microwave brain imaging system to detect brain tumor using metamaterial loaded stacked antenna array