Wide bandwidth high gain circularly polarized millimetre-wave rectangular dielectric resonator antenna

A wideband high gain circularly polarized (CP) rectangular dielectric resonator antenna (RDRA) having a frequency range of 21 to 31 GHz is proposed. The RDRA consists of two layers with different dielectric permittivities and has been excited using a cross slot aperture. The proposed antenna offers wide impedance and CP bandwidths of ~36.5% and 13.75% respectively, in conjunction with a high gain of ~12.5 dBi. Close agreement has been achieved between simulated and measured results

Wideband high-gain millimetre-wave three-layer hemispherical dielectric resonator antenna

A wideband high gain three-layer hemispherical dielectric resonator antenna (HDRA) that operates at TE511 and TE711 higher order modes is proposed. The HDRA is composed of three layers, which has permittivities of 20, 10 and 3.5. The multilayer structure has been chosen in order to reduce the Q-factor and achieve a wider impedance bandwidth. Cross slot feeding mechanism has been utilized taking into account the excited higher order modes for gain enhancement. The proposed antenna provides an impedance bandwidth of 35.8% over a frequency range of 20.8 to 29.9 GHz in conjunction with a high gain of ~9.5 dBi. The proposed DRA represents the first attempt in utilizing a mm-wave hemispherical DRA

A Pattern Reconfigurable Microstrip Dipole Antenna with PRS Gain Enhancement

This paper investigates a low complexity high gain structure that can switch the radiation pattern from boresight to almost endfire direction. The principles of Fabry Perot, reconfigurable parasitic reflectors and partially reflective surfaces are combined to achieve the pattern reconfigurability. Two different Fabry-Perot cavity spacings are assessed and a maximum gain of 18.8 dBi is achieved at boresight which can be reduced by over 12dB with the use of PIN diode switches. Radiation towards the endfire directions has a maximum gain of 7.1dBi which can be reduced by almost 17dB with the use of the PIN diode switches. The paper presents numerical simulations of the proposed antennas

Dual-band circularly polarized cylindrical dielectric resonator antenna for millimeter-wave applications

This paper presents a compact dual-band circularly polarized cylindrical dielectric resonator antenna (CDRA) that operates at 38 and 60 GHz. The proposed design is contained a single wafer of silicon and two annular slots to exciting the DRA. Shorted outer and inner annular slots implemented to generate circular polarization in both bands. The proposed design of CDRA achieves a 3-dB AR bandwidth of 3.34 and 7.53%, with an impedance bandwidth of 9.74 and 24.01% at lower and upper bands, respectively. Also, it has excellent radiation characteristics, which its radiation efficiency and peak gain of 7.6 dBi and 95.22%, respectively. The proposed CDRA with dual-band resonances and gain bandwidth has the excellent potential to be applied for mmwave wireless communications at the 38/60 GHz bands

An efficient photomixer based slot fed terahertz dielectric resonator antenna

A slot fed terahertz dielectric resonator antenna driven by an optimized photomixer is proposed, and the interaction of the laser and photomixer is studied. It is demonstrated that in a continuous wave terahertz photomixing scheme, the generated THz power is proportional to the 4th power of the surface electric field of photocondutive layer. Consequently, the optical to THz conversion efficiency of the proposed photomixer has an enhancement factor of 487. This is due to the fact that the surface electric field of the proposed photomixer with a 2D-Photonic Crystal (PhC) superstrate has been improved from 2.1 to 9.9 V/m, which represents a substantial improvement. Moreover, the electrically thick Gallium-Arsenide (GaAs) supporting substrate of the device has been truncated to create a dielectric resonator antenna (DRA) that offers a typical radiation efficiency of more than 90%. By employing a traditional coplanar strip (CPS) biasing network, the matching efficiency has been improved to 24.4%. Therefore, the total efficiency has been considerably improved due to the enhancements in the laser-to-THz conversion, as well as radiation and matching efficiencies. Further, the antenna gain has been improved to 9dBi at the presence of GaAs superstrate. Numerical comparisons show that the proposed antenna can achieve a high gain with relatively smaller dimensions compared with traditional THz antenna with Si lens

Full embroidery designed electro-textile wearable tag antenna for WBAN application

A flexible and totally wearable textile antenna is proposed by embroidering the conductive threads into garments. A purely polyester substrate has been utilized, which provides a tag that can be easily integrated with the clothes. The proposed tag antenna is small with dimensions of 72 × 20 × 2.75 mm3 and offers an enhanced performance in terms of gain and stability when worn on different body locations. Experimental results demonstrate an improved impedance matching owing to the elasticity of the E-shaped inductive feeder. Close agreement has been achieved between the simulated and measured results

CPW fed compact UWB 4-element MIMO antenna with high isolation

In the paper, an extremely compact multiple-input-multiple-output (MIMO) antenna is proposed for portable wireless ultrawideband (UWB) applications. The proposed prototype consists of four monopole antenna elements, which are placed perpendicularly to achieve polarization diversity. In addition, the mutual coupling between antenna elements is suppressed by designing the gap between the radiation element and the ground plane. Moreover, a matching stub has been connected to the feedline to ensure impedance matching in high frequency. Both simulated and measured results indicate that the proposed antenna has a bandwidth of 3–20 GHz, with a high isolation better than 17 dB. In addition, the designed MIMO antenna offers excellent radiation characteristics and stable gain over the whole working band. The envelope correlation coefficient (ECC) is less than 0.1, which shows that the antenna can meet the polarization diversity characteristics well

Microstrip Patch Antenna Array Mutual Coupling Reduction using Capacitive Loaded Miniaturized EBG

In this paper, a compact miniaturized EBG loaded with surface mounting capacitor has been developed. The dimension of the EBG patch with approximately λ/36 has been achieved with dimension highly dependent on the capacitor values. The integration of the capacitive loaded miniaturized EBG with a couple of microstrip patch antenna has reduced approximately 12dB mutual coupling within the elements at the antenna resonance frequency of 2.2GHz. The antenna E-plane gain has been improved for more than 2dB with 3dB reduction in side lobes when comparing the traditional array with the array integrated with EBG. The propagation characteristics and gain of the array have been analyzed using CST Microwave Studio (CST MWS). The measured results have shown good agreement with the simulated results. The miniaturized EBG will be very useful in minimizing the space within the array antenna especially for the MIMO applicatio

Comparative Study of Wound Healing After Treatment With Crude Date Extract and Silver Sulphadiazine

Crude date extract in comparison with silver sulphadiazine was tested to evaluate their effects on wound healing and their antimicrobial activities against the growth of Staphylococcus aureus. Crude date extract 5% (w/v) and silver sulphadiazine 20% (w/v) inhibited the growth of Staphylococcus aureus by 67% and 87% respectively. However,10% and 20% (w/v) date extract showed 100% inhibition. Date extract was fractionated using different solvents with different polarities; all fractions were tested for their antimicrobial activities. Ethyl acetate fraction was found to have inhibitory activity against the growth of Staphylococcus aureus. Preparative TLC was done for ethyl acetate fraction which was further identified to be terpenoidal compound. The histological changes in healing wounds have also been investigated after treatment with 20% and 40% crude date extract ,and silver sulphadiazine and amoxicillin by light microscopy.  The results obtained from 20% CDE treatment as compared to untreated control indicated that, this treatment promotes the process of wound healing and stimulates fibroblast, collagen and epithelialization significantly. This effect was comparable with the effect of silver sulphadiazine treatment