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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]

A super-compact ultra-wideband (UWB) microstrip band-pass filter (BPF) with good selectivity and wide stopband is proposed in this paper. The super-compactness along with wide stopband of the proposed filter is achieved by integrating modified multimode resonator-based UWB BPF and defected ground structure (DGS)-based compact low-pass filter (LPF). The LPF structure is designed using four non-uniform configurations of DGS units along with a 50 Ω microstrip line. Each DGS unit is formed by cascading three isosceles U-shaped DGSs. Further, an equivalent RLC circuit model of the LPF is proposed to validate the numerical simulation and experimental results of LPF. The proposed filter has simulated passband frequency range 3-11 GHz with wide stopband: attenuation better than 40 dB and 25 dB over the frequency ranges 11.7-20.5 GHz and 11.2-30 GHz respectively. The experimental results for the proposed filter are nearly in agreement with corresponding numerical simulation results. [ABSTRACT FROM AUTHOR]

ABSTRACT To mitigate the interference with coexisting wireless systems operating over 3.3-3.6 GHz, 5.15-5.825 GHz, and 7.725-8.5 GHz bands, a novel triple band notched coplanar waveguide fed pitcher-shaped planar monopole antenna is presented for ultrawideband applications. Bands notched characteristics are achieved using a novel mushroom type electromagnetic band gap structure like resonator and a split ring slot. A conceptual equivalent RLC (Resistor-Inductor-Capacitor)-resonant circuit is presented for the band notched characteristics . Furthermore, the input impedance and VSWR (voltage standing wave ratio) obtained from the equivalent circuit are validated with simulated and measured results. Performances of the antennas in both, the frequency domain and the time domain are investigated. The simulated and measured results demonstrate that the proposed antennas have wide impedance bandwidth, nearly stable radiation patterns, and suppression of gain and total radiation efficiency at notched bands. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:795-806, 2015. [ABSTRACT FROM AUTHOR]

A small size, planar and co‐planar waveguide fed metamaterial inspired antenna is proposed for ultra‐wideband (UWB) application. The main radiating element consists of three split‐ring resonators (SRR) and placed along one axis. Moreover, coplanar waveguide (CPW)‐fed line along with modified ground plane is used to improve the impedance matching. The physical size of proposed antenna is 25(W) × 22 (L) × 1.6 (H) mm3. The CPW‐fed metamaterial inspired antenna provides bandwidth of 10.4 GHz from 3.1 to 13.5 GHz based on the 3:1 (voltage standing wave ratio [VSWR] <2). Over the range of UWB frequency, peak realized gain varies from 2.5 to 4 dBi. The proposed antenna provides omnidrectional radiation patterns. Further, fidelity factor of the proposed antenna is also calculated and measured. The calculated fidelity factor is suitable for UWB applications. Finally, prototype of the antenna is developed and tested using network analyzer. The simulated and measured results are in good agreement. [ABSTRACT FROM AUTHOR]