This paper presents a new approach for the design of high-gain and wide-bandwidth planar antenna arrays. It is based on the coupling matrix theory which allows the design of the arrays using all-resonator structures. The parameters of the matrix offer the flexibility of achieving a controllable bandwidth. They also introduce a frequency filtering functionality into the arrays which can remove the need to place a bandpass filter after the arrays at the very front end of a communication system. The new approach has been applied to using novel topologies to form two wideband 4×4 planar antenna arrays utilizing rectangular waveguide cavity resonators operated at X-band frequencies. The first topology is seventh order and based on 39 resonators configured in two waveguide-layers; that is one layer for the feed resonators and one layer for the radiating resonators. The second topology is fourth order based on 25 resonators configured only in a single waveguide-layer. Fabrication and measurements have been performed, showing very good agreement with the simulations.

The detection of branded and unbranded chemical materials is essential for the quality control assessment. In this work, a metamaterial inspired sensor is designed and fabricated, which incorporates oval-shaped wing resonators, in order to use to detect branded and unbranded diesels in the X-band frequency region. The simulation studies were carried out by using the Computer Simulation Technology (CST) Microwave studio. A transmission line was introduced into the sensor design and genetic algorithm was used to optimize the proposed structure. Parametric study was investigated by changing the permittivity, permeability of the sensor layer, width of the transmission line, materials of the substrate layer, and width of the resonator. Results showed that different factors can be considered to sense the chemical materials including the shift in resonant frequency and amplitude variation in the reflection or transmission spectrum. It was found that the sensible variation in the transmission value is about −3.2 dB, which is superior to that reported in literature. It was concluded that the sensor is highly sensitive to distinguish the branded diesel from the unbranded one, which makes it viable for detecting fluidics in the chemical industry and medicine.

Microstrip patch antennas have been used in many applications since their appearance. Despite their great promise, their narrow bandwidth and the loss at high-frequency bands have limited their usage in medical applications. This work proposes a developed low-cost microstrip patch antenna suitable for microwave imaging (MWI) applications within the wideband frequency range. The proposed antenna is loaded with an artificial magnetic conductor (AMC) to improve the antenna performance. The simulated results obtained using computer simulation technology (CST) indicate that the presence of the AMC has improved the frequency selectivity of the antenna at 8.6 GHz with a peak realized gain of 9.90443 dBi and 10.61 dBi for simulated and measured results, respectively. The proposed microstrip antenna has been fabricated to validate the simulated results, and its performance is tested experimentally. Additionally, the fidelity factor of face-to-face (FtF) and side-by-side (SbS) scenarios have been presented. The breast phantom models with a tumor and the antenna operating as a transceiver have been numerically simulated for the application of cancer tumor cell detection. The work will have a significant impact on the design of electromagnetic biosensors.

This paper presents a new design of the microstrip patch antenna operated at the terahertz frequencies (700-850 GHz). The conventional microstrip patch antenna dimensions shrink to a few microns when operating at such terahertz frequencies. Thus, the design of the patch and its feeding network will be miniaturized extremely, and their fabrications would be extremely difficult. In this paper, the configuration of the proposed microstrip patch antenna is suited in a way that it can be modeled using multilayers structure. This multilayer structure facilitates the modeling, and considering its fabrication. The proposed microstrip antenna has been designed using three layers. The top layer is used to model the rectangular patch; while the second layer is for the substrate, and the bottom layer is for the ground plane. The physical dimensions of the layers and the fed-line are optimised using the microwave Computer Simulation Technology (CST) simulator in order to enhance the electrical parameters of the antenna such as antenna realised gain, bandwidth, total and radiation efficiencies, and radiation patterns. In addition to that, the impact of the physical dimensions of the rectangular patch on controlling the resonant frequency of the dominant mode (TM01) have been investigated. Keeping the lower and higher propagating modes out of the frequency band of interest is another aspect which has been addressed in this paper. The antenna has been simulated, and its realised gain fluctuates from 6.4 dBi to 9.7 dBi over the operating frequency range (700-850 GHz). Also, it provides extremely large reflection coefficient bandwidth (S11) which it is below -10 dB over the entire operating frequency band. The total efficiency is more than 75 %. Due to its simplicity and providing large bandwidth, the proposed antenna could be of interest in many security and surveillance applications.

Improvement in the antenna gain is usually achieved at the expense of bandwidth and vice versa. This is where the realization of this enhancement can be made through compromising the antenna profile. In this work, we propose a new design of incorporating periodic metasurface array to enhance the bandwidth and gain while keeping the antenna to a low-profile scheme. The proposed antenna was simulated and fabricated in order to validate the results in the operating frequency range from 10 MHz to 43.5 GHz. Computer simulation technology (CST) microwave studio software was used to design and simulate the proposed antenna, while LPKF prototyping PCB machine was utilized to fabricate the antenna. Results showed that the antenna generated a gain and bandwidth of 14.2 dB and 2.13 GHz, respectively. Following the good agreement between the numerical and measurement results, it is believed that the proposed antenna can be potentially attractive for the application of satellite communications in Ku-band electromagnetic wave.

This letter presents the design of a 3 ^rd order filtering waveguide aperture antenna based on coupled cavity resonators. Three offset-coupled rectangular waveguide cavities are employed in the design realizing two nested loaded-stubs without costing extra structure and size. The loaded-stubs introduce two controllable transmission zeroes and enhance the out-of-band realized gain selectivity. To validate the predicted results, a prototype operating at the X- band frequencies has been fabricated monolithically using the 3-D selective laser melting printing technique. The measured results are in very good agreement with the simulated results, showing a flat gain response of 7.0 ± 0.2 dBi from 9.5–10.5 GHz with very good out-of-band selectivity. The fractional bandwidth is about 10% at 10 GHz when S ₁₁ = -20 dB. Compared to the previously designed filtering antennas, the proposed design has the advantages of stronger out-of-band gain selectivity and low profile.