In this work, a beam‐steering array antenna for pattern stabilisation is presented. The antenna element consists of two layers with a unique structure of microstrip to coplanar waveguide (CPW) transition to cover a frequency range from 20 to 30 GHz and a stable pattern at all operating frequencies. To increase the gain of the antenna element, an elliptical broadband Fabry–Perot cavity structure is used. The element manages 3 dB gain bandwidth of almost 23–26 GHz with a 14.4 dBi peak. In addition, a modified Butler matrix consisting of two 90° and two 135° couplers without phase shift section is used to attain a stable pattern. The proposed Butler matrix performs a stationary phase with a phase error of less than ±6° over a frequency band from 21 to 29 GHz. The integration of the proposed element and feed network leads to a beam‐tilting antenna capable of managing its patterns through the input ports in the operating frequency range of 20–29.5 GHz (9.5 GHz) and 20.6–29.6 GHz (9 GHz) for ports 1 and 2, respectively.

In this work, a high-gain circularly polarised (CP) substrate integrated waveguide (SIW) bow-tie antenna is presented. The proposed antenna includes a pair of bow-tie radiators. To centralisation radiated pattern and recede side lobe and back lobe level two tilted rows of metalised via hole at the end of the SIW feed line is used. The methods of increasing the antenna gain and generating the CP are discussed. The proposed antenna was fabricated to validate simulated results. The designed structure operates across 40-68 GHz and exhibits a gain of 10-12.5 dBic. In addition, the proposed antenna exhibits a 3-dB axial ratio bandwidth from 54 to 64.3 GHz.

The L-shaped extraction pulsed plate column is believed to be able to perform under operating conditions between those of the vertical and the horizontal pulsed plate columns. It has an extraction efficiency similar to the vertical pulsed plate column. Here, the mass transfer performance of this novel column type was investigated and the application of three different models, i.e., the plug flow, the axial dispersion, and the back flow models, was evaluated to predict the solute concentration profile along the column length. The water-acetone-n-butyl acetate and the water-acetone-toluene systems were used. The influence of the operational parameters on the height of the mass transfer unit and the back flow coefficients was evaluated using the back flow model. New correlations were proposed to predict the height of the mass transfer unit along with the back flow coefficients in each phase, which were in satisfactory agreement with the experimental data.

This article examines a substrate integrated waveguide (SIW) cavity‐backed circularly polarized diversity antenna. In the proposed novel antenna, parasitic patch and reconfigurable diodes are used to change polarization diversity from left hand to right hand and vice versa, respectively. In addition to, what makes distinctive proposed antenna in compared with similar works, is ability to change linear polarization from a SIW slot to circularly polarization by a parasitic patch. Chopping off two diagonally opposite corners makes the resonance frequency of the mode along this diagonal to be higher than that for the mode along the unchopped diagonal. By exciting parasitic patch with a slot along axes of it the orthogonal modes are generated which causes to CP. The comparison between simulation and measurement results validate antenna design. The measured impedance BW (VSWR < 2) for state 1 and 2 are 22.18% (11.86‐14.82 GHz) and 21.68% (11.88‐14.77 GHz), and The measured 3‐dB AR BW for states 1 and 2 are about 11.46% (11.43‐12.82 GHz) and 11.23% (11.43‐12.79 GHz), respectively. Finally, the measured maximum gain is 9.81 dBic.

A novel configuration of a Fabry-Perot resonator (FPR) antenna for C band application, which produces a high gain, wider impedance and 3-dB axial ratio bandwidth is presented. Radiation element of the antenna is a square patch coupled with four points of crossed aperture. A feed network can change the rotation of the phase in aperture points and, by this technique, change the polarisation diversity (PD). This antenna is capable of variation circularly PD by changing the input port, also partially of the reflective surface which plays as the role of FPR resonator due to the structure and arrangement of cells capable of changing the PD. Experimental results clarify that the FPR antenna covers the impedance bandwidth of 4-6 for S11 ≤ −10 dB. Furthermore, the proposed antenna approximately has a constant gain from 4.4-7.5 GHz with a peak value of 18.1 dBic for each of the input ports. The antenna covers 3 dB axial-ratio bandwidth, between 4.35-7.85 GHz.

This article presents a novel compact size (20 mm × 16 mm × 0.8 mm) Tai‐chi‐shaped antenna for wireless applications. Dual frequency operation (3.14–4.58 GHz and 4.97–6.53 GHz) is achieved by optimizing the antenna during designing steps. The antenna gives circulary polarization from 3.26 to 4.42 GHz and from 5.45 to 6.63 GHz frequency ranges. The 4.2 dBic stable gain is another evident advantage of proposed work.

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