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In this paper, a novel metasurface-based Fabry–Perot Cavity antenna is presented. The antenna is wideband, directive and has a high front-to-back ratio. The idea of the antenna is based on loading a microstrip narrow band patch antenna resonating at 4.6 GHz by a metasurface superstrate. The metasurface superstrate consists of an aperiodic array of holes in contrast to the periodic nature of unit cell previously explored in the literature. The metasurface is designed as a near-zero-refractive-index material (NZRIM). By controlling the phase reflection properties of the structure, improved radiation pattern, improved front-to-back lobe ratio (7–25 dB), improved directivity (by 3 dB) and antenna bandwidth (five times) are obtained compared to a conventional microstrip antenna. The enhancement in bandwidth and directivity simultaneously using just a single layer of metasurface superstrate demonstrated for the first time, to best to authors' knowledge, are obtained. [ABSTRACT FROM AUTHOR]

This paper presents analysis and experimental measurements of CPW and microstrip compact monopole antennas loaded with resonator circuits inspired from simplified half-mode composite right / left-handed unit cell. The antennas were designed to have a typical omnidirectional radiation pattern. The CPW fed dual-band antenna resonates at 2.4 and 5.8 GHz, respectively. The antenna size is 20 × 30 mm2 and the radiator patch is only 25% at 2.4 GHz and 60% 5.8 GHz in comparison with a conventional patch antenna. The microstrip triple-band antenna covers the frequency bands from 2 to 2.4 GHz, 5.4 to 6 GHz and 6.8 to 8 GHz. The antenna size is 28 × 25 mm2 which is less than 25% at lower frequency band compared to the size of the conventional patch antenna. Detailed theoretical and full-wave analysis is presented and experimental results demonstrate a good agreement between the measured and the simulated. The suggested antennas can be employed for compact size and multi-band functionalities in wireless applications. The loading technique can be adapted for more frequency bands. [ABSTRACT FROM AUTHOR]

In this paper, we introduce a compact dual-band two-element array antenna in a substrate integrated waveguide (SIW) configuration for C-band applications. A new geometry based on an asymmetric composite right–left-handed transmission line cells was suggested for the single antenna element. The proposed geometry has the advantage of having arbitrary dual-frequency design. The array elements are fed with a wideband SIW impedance transformer. The results indicate that the proposed antenna element size is only 15 × 12.8 mm2, which approximately represents up to 70% size reduction at similar frequencies. The radiation properties of the array antenna have broadside radiation pattern at the two bands. The detailed analytical design explanation, full wave simulations, and experimental measurements are introduced. [ABSTRACT FROM AUTHOR]

This paper presents an ultra compact dual-band coplanar waveguide metamaterial filter based on generalized metamaterial transmission line. The detailed theoretical design steps of the filter are explained. The dual-band filter design performance has been validated using equivalent circuit modeling, electromagnetic full wave simulations, and practical measurement. The results illustrate the filter has dual passbands centered at 0.82 and 1.48 GHz with approximately 1 dB insertion loss and minimum 12 dB return loss. Good agreements between the circuit modeling, electromagnetic full wave simulations, and practical measurements are achieved. Moreover, the filter size is only (18 × 28 mm2) which is only less than (0.2λg × 0.31λg) at the center frequency of the first passband and (0.36λg × 0.56λg) at the center frequency of the second passband. [ABSTRACT FROM PUBLISHER]

In this paper, a validation study for the metamaterial accurate modelling using the electromagnetic numerical transmission line matrix (TLM) computation method is presented. In our work, the three-dimensional symmetrical condensed node (SCN) TLM algorithm has been modified to fully simulate non-linear and dispersive metamaterial structures. The modification code principles have been explained theoretically. The propagation computation using our modifying TLM code has been tested for a metamaterial ground slab loaded by split ring resonator structure. The tested structure acts as a metamaterial radar absorber. Moreover, experimental measurements were carried out and compared to the computed ones. The results confirmed the good agreement between measured and TLM computed results. Furthermore, the propagation computation was confirmed by measuring the backscattering for different incident angles which demonstrate very good agreement for our modified TLM code. The measurement results confirm the versatility and power of the modified SCN TLM algorithm to handle metamaterial structures. [ABSTRACT FROM AUTHOR]

A compact low-loss microstrip diplexer with four controllable transmission zeros (TZs), all less than 41 dB, is presented. The diplexer circuit consists of two coupled gap bandpass filters with a T-junction as a combining circuit. Channels' filters metalize SIW resonators loaded with metamaterial cells operated at zeroth order mode for compactness and low loss operation. For each channel, a fractional bandwidth of 1.9% is obtained. Also, two TZs at both sides of the resonant frequency are obtained by mixed electric and magnetic coupling between channels' resonators. Design methodology for filtering response and placing TZs at certain frequencies are discussed in detail. There is a good agreement between simulation and measurement with isolation better than 40 dB. Moreover, the diplexer has a small size of (1.1×1.43 λg2). Lower and higher TZs are located at 4.75 and 5.69 GHz, for the lower channel, and at 5.4 GHz and 6.2 GHz for the higher channel, respectively. [ABSTRACT FROM AUTHOR]