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In this article, a metamaterial absorber structure is analyzed using the transmission line method (TLM) considering the normal incidence of the wave. The unit cell of the presented absorber structure is a composite geometry providing dual‐band absorption. Peak absorptivities of 95.02% and 99.84% are obtained at 4.215 GHz and 10.95 GHz, respectively. The experimentally validated simulated reflection response is used as a reference to validate the analytical response of the absorber structure. To obtain the equivalent circuit model, the frequency selective surface (FSS) forming the absorber top layer is considered as a combination of two simpler FSS. The individual absorbers formed by two such FSS are correctly modeled using TLM. The obtained equivalent circuits are then combined suitably by incorporating the involved coupling capacitances into the calculation. The analytical and simulated response of the presented absorber structure is found in good agreement. The presented decomposition approach for the development of a circuit model of the composite FSS is promising and it would pave the way in obtaining the good physical insight of the multiband metamaterial absorber structures. [ABSTRACT FROM AUTHOR]

ABSTRACT A compact, multiband, shorted monopole antenna is presented for ultraslim mobile handsets. The proposed antenna is formed by a simple structure of three radiating strips of different length namely, λ/4 C-shaped radiating strip, 3λ/8 meandered line radiating strip, and a λ/4 shorting strip. Which results in proposed antenna that covers GSM850/900/1800/1900/UMTS/Wi-Fi/LTE2300/2500/WiMAX bands with respect to −6 dB impedance bandwidth. The measured peak realized gain is observed between 1.2 and 4.2 dBi while simulated total radiation efficiency is between 60 to 93% in the operating bands. The proposed antenna is investigated in free space as well as in actual mobile environment consisting of mobile plastic housing along with large metallic display screen and battery. Specific absorption rate computation is also carried out on human head phantom in vicinity of the proposed antenna and obtained well below the specified limit. The parametric analysis is also carried out to understand the effect of the shape parameters of the antenna. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1459-1466, 2015 [ABSTRACT FROM AUTHOR]

ABSTRACT A compact dual-band multiple-input multiple-output (MIMO) antenna is presented for wireless local area networks (2.45/5.8 GHz) applications in mobile handsets. The proposed MIMO antenna consists of two planar inverted-F antennas loaded with inverted J-shaped slot and inverted L-shaped slot. The defected ground structure of fork shaped slot is proposed between antenna elements to achieve high port-to-port isolation (<−20 dB). The distribution of specific absorption rate (SAR) over 1-g and 10-g tissues in human head are also studied for two different positions of the antenna at 2.45/5.8 GHz frequencies through SAR to PEAK location spacing ratio (SPLSR) according to Federal Communication Commission standard. The values of SPLSR are observed over 1-g of tissues between 0.107 and 0.246 W/kg/cm and 0.304-0.122 W/kg/cm and over 10-g of tissues between 0.242 and 0.124 W/kg/cm and 0.154 and 0.045 W/kg/cm at 2.45 GHz and 5.8 GHz, respectively. The S-parameters, surface current distribution, diversity parameters, and radiation patterns are presented. The fabricated prototype are measured and obtained good agreement with simulated results. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:906-912, 2015 [ABSTRACT FROM AUTHOR]

A dual-band L-strip proximity fed shorted rectangular microstrip antenna is proposed and investigated theoretically simulated by HFSS and experimentally. Proposed radiating patch is located about (17.5 mm) above the ground plane. Return Loss and co- and cross polar radiation pattern are presented. Computed and measured results of return loss are in good agreement. The effect of the geometric parameters of the proposed antenna, such as length of the vertical and horizontal portion of the L-strip is also investigated. The impedance bandwidth (-10 dB return loss) 32.5% (calculated) and 33.00% (measured) for the proposed antenna are achieved for optimized antenna design. Significant size reduction (i.e., ∼85%) is obtained as compared with conventional rectangular patch of same resonant frequency. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1567–1571, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25235 [ABSTRACT FROM AUTHOR]

A wide-band L-strip proximity fed rectangular microstrip antenna is proposed and investigated both theoretically and experimentally. The radiating patch is located about 0.1λ0 (16.5 mm) above the ground plane. The broadband characteristic of antenna is achieved by employing a thick substrate (0.1λ0). Numerical results for the input impedance, VSWR, and co- and cross-polar radiation pattern are presented and compared with the measured results. Good agreement is obtained between computed and measured results. The effects of the geometric parameters of the L-strip like length of the vertical and horizontal portion of the strip are investigated. It is found that the antenna attains 48.36% impedance bandwidth (SWR ≤ 2) (theoretically) and 56.67% (experimentally) for optimized antenna design. The H-plane cross-polarization level is quite high (-16 dB) especially at (computed θ ≈ 60°, and measured θ ≈ 40°) whereas the E-plane cross-polarization level is very low. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1817–1824, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22634 [ABSTRACT FROM AUTHOR]