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A rectangular microstrip patch (RMSP) antenna is designed to be used in a two-element Multi-Input Multi-Output (MIMO) antennas at which they operate at 5.8 GHz. The two antennas are positioned opposite to each other with a separation of 10 mm (0.2 λ0) from their radiating edges. A novel uni-conductor electromagnetic bandgap (UC-EBG) periodic cells are introduced in this paper as effective barriers for surface waves compared to the conventional UC-EBG. Each unit cell has a compact size area 7.3 × 5.8 mm2 where it is 20% more compact than the conventional cell. Two of the proposed modified EBG periodic cells are placed in-between the two antennas causing an excellent reduction in the coupled power of 46 dB. This strong isolation definitely enhances the performance of antennas in MIMO communication systems, where 0.0001 and 0.03 values for correlation coefficient have obtained from S-parameters and far-field information, respectively, due to this strong isolation.

In this paper, an efficient technique proposed for surface wave filtering in radar array antennas. The filtering reduced the correlation between high directive TX/RX array antennas. The filtering has been done using a small defected ground filter that achieves more than 20 dB isolation between the two antennas with a very close separation between the two antennas (less than 0.06 λ0). The presented results confirm the advantage of the applied technique in reducing the correlation coefficient between the two antennas to less than 0.005. The results demonstrate that 99.68% of coupled power can be reduced. The integrated isolated radar array antennas have been studied theoretically, simulated using electromagnetic simulation, and measured experimentally.

This paper presents the experimental verification of the tunable characteristics of a ferrite composite right/left handed coupled line coupler. The coupler is designed using two coupled CRLH-CRLH transmission lines. The coupler is designed to demonstrate equal through and backward coupling. The novel coupler has been designed and realized in coplanar waveguide configuration on a ferrite substrate. The tunable characteristics are achieved by changing the applied DC magnetic bias to the ferrite substrate. The measurement results reveal that the coupler’s fractional bandwidth can be tuned from 29% to 69% by varying the applied DC magnetic bias from 1000 Oe to 1750 Oe. Within the tunable bandwidth, the maximum backward coupling is −5 dB. The coupler has high forward coupling isolation, close to −30 dB at its centre operating frequency. In addition to its tuning capability, the coupler has the advantages of its compact size; it has the length of 11.5 mm and not-so-tight line separations of 2.5 mm. Furthermore the coupler only requires low DC magnetic bias.

In this study, a resistor-loaded wideband conformal metamaterial absorber has been designed, fabricate, and analyzed experimentally. The proposed absorber consists of lumped resistors loaded on cross-shaped resonators at the top side of the flexible substrate and copper metal film separated by flexible foam on the substrate's backside. The total thickness of the absorber is 0.07λo, where λo is the lowest absorption frequency. The simulated results exhibited absorption from 3.25 - 13.6 GHz (absorption bandwidth 123%). The wideband absorption mechanism of the absorber was analyzed through the equivalent circuit model and parametric study. The designed structure has been tested on the planar and curved surfaces and measured the results. The simulated and experimental results have good agreement between them. The designed absorber can be suitable for scientific and military applications as of its wideband absorption bandwidth, polarization-insensitive, and conformability.

In this paper, the time domain analysis of an Ultra Wide Band antenna flexible circular monopole antenna is presented. The antenna is fabricated on liquid crystalline polymer flexible substrate with a compact geometry that makes it suitable for wearable applications under different bending conditions. The antenna is fed by coplanar waveguide transmission line and has a compact total size of 40 × 22 mm2. Moreover, the antenna has good radiation efficiency (97%) over the bandwidth. The presented antenna has a good performance over the operating spectrum for straight and bending configurations. The design principals along with simulation and experimental results are presented in this contribution.

In this paper, two different triple band dipole antennas loaded by new modified composite right left handed cell are presented. The modified cell can introduce large electrical length in small size. Thus, the two antennas are designed with smaller operating frequency or reduced physical length compared to a single frequency reference dipole. The designed antennas can serve different wireless services for GPS (1.27 GHz and 1.55 GHz), UMTS (1.85 GHz), and WiFi (2.4 GHz) in triple band functionalities. The lower operating frequency antenna size is (70 × 70 mm2) whereas the reduced physical length antenna size is (60 × 70 mm2). At mid band frequencies the reduced frequency antenna length is (0.29 λ0, 0.37 λ0, and 0.52 λ0), whereas that of the reduced physical length is (0.28 λ0, 0.41 λ0, and 0.56 λ0), at triple band mid frequency, respectively. Compared to a typical dipole antenna, the designed loaded dipoles can achieve a length reduction that can reach up to 50%. Moreover, the antenna has good gain at the triple bands (−1.2 dB, 1.9 dB and 3.5 dB for reduced operating frequency antenna and −3.1 dB, 1.2 dB and 3.4 dB for the reduced length antenna. The two antennas have good radiation efficiency that can reach up to 84% on a low cost antenna substrate. The mathematical analysis, full wave simulation and experimental measurements of the reported antennas are introduced.

A design of CRLH MIMO metamaterial with reversal CRLH configuration antenna is presented. The two antenna elements are designed to operate at 5.8 GHz for wireless applications. The two antenna elements are designed using reversed one left handed unit cell for high mutual coupling isolation in close separation. The two elements of MIMO antenna are put together with very small separation between them where the distance between the edges of two antenna elements is only 0.034 λ 0 . The MIMO antenna has compact size (its size is only 2.93 × 2.6 cm 2 ). The designed antenna elements have better than 35 dB coupling isolation between the two inputs without using extra structures. The performance of MIMO antennas is evaluated by studying the correlation coefficient, diversity gain and total active reflection coefficient. A good agreement is achieved between simulation and measured results.

A flexible paper based and dual-band antenna is designed for UMTS service (1.9 GHz) and WiMAX services (5.8 GHz). Flexible paper is used as a substrate for the printed antenna. Expanded graphite ink is used to enable printing the antenna on the substrate. The antenna has been designed, simulated, fabricated, and measured. Steps of preparing the conductive printed ink and fabrication of the antenna have been discussed. The conductivity of the printed antenna is measured to be 1 × 104 S/square and the thickness is also measured with an average of 30 µm. Through the whole paper, good agreement between simulated and measured results is satisfied. In addition to the achieved flexibility, the antenna has demonstrated good measurement results. First, the antenna has a bandwidth of 300 MHz at 1.9 GHz and 400 MHz at 5.8 GHz with fractional bandwidth of 15.7% and 6.8% at the both bands, respectively. Second, the measured antenna radiation pattern has indicated that it is omnidirectional at 1.9 GHz and approximately omnidirectional at 5.8 GHz. Third, The antenna gain is 1.266 dB and 0.512 dB at the two bands, respectively. Finally, the antenna’s efficiency at the both bands is 35% and 55%.