Yaqeen Sabah Mezaal

This paper presents firstly the literature review and then investigates the design, simulation, and performance analysis of a compact microstrip bandpass filter (BPF) for wireless communication, IoT, and radar systems as candidate for TWIN OPEN LOOP RESONATORS in our future studies of filter and diplexers. Using ROGER RT (RO3003), an open-loop square with two SIRS at the top of the resonator structure is investigated for the filter, which is optimized to operate at the center frequency of 3,82 GHz with an external quality factor of 57,88. Regarding S-parameter results, the performance is good, with an insertion loss of 0,41 dB, while a high return loss is achieved at 21,66 dB. Such characteristics guarantee good selectivity and low signal distortion at an upper band of 83,74 dB /GHz with a transition band of 0,269 GHz. The proposed BPF has a transmission zero of 71,53 dB at 4,427 GHz with a compact size of 18 mm × 18 mm.

This study presents new miniaturized designs of microstrip multiband bandstop filter (BSF) and multiband bandpass filter (BPF) employing step impedance resonators (SIRs) and RT/Duroid 6010 substrate. The projected bandstop filter can be adopted in applications for removing the interference of narrowband signals from the allocated bands of other wireless systems operated under 2.5, 5.84, and 9.79 GHz. On the other hand, the designed bandpass filter can be used in RF transceivers operating in various isolated narrow frequency bands at operating frequencies of 5.35, 5.555, 6.36, 7.84, 8.385, and 9.5 GHz. The novelty of this paper comes from the considerable smallness of the designed filters and extremely low fractional bandwidths (less than 1%) as compared with numerous reported filters in the literature, especially the superconducting filters. Both filter designs have been verified through measurement, and the measured consequences are in line with the simulation ones.

In this study, two new printed slot antennas have been simulated and fabricated using a single layer of FR4 substrate for modern wireless applications. The first printed slot antenna with etched stair-step topology in the ground plane is proposed to achieve the single-band operation. This topology is based on two components of asymmetrical step-impedance resonator (SIR) and one component of symmetrical SIR. The first designed printed slot antenna satisfies the requirements of WLAN applications at 5.75 GHz. The second printed slot antenna is a developed version of the first one with one inserted component of symmetrical SIR and one asymmetrical SIR component to be operated as a multiband antenna applicable for WiMAX, WLAN, and X-band downlink satellite systems at 3.5, 5.75, and 7.75 GHz, respectively. The proposed antennas have small sizes, and competitive electrical specifications than many reported SIR and non-SIR antennas in the literature.

Euclidean and fractal terms are mathematically and physically important terms in antenna design, but rarely reported studies had discussed these terms together in antenna design in their texts. This paper first gives an overview of Euclidean and fractal antennas with useful and satisfactory facts. Four printed slot antennas are then studied using Euclidean slot shapes printed in the ground plane with and without Euclidean patches using FR4 substrate. These antennas are employed to investigate their suitability as simple alternatives to complicated fractal geometries and their specific formulas. Parametric analyses with feedline lengths and patch scaling aspects are adopted to generate single, dual, and multiband responses. These parametric studies provide different outcomes and choices for antenna electrical specifications suitable for various wireless applications. It is clear that inserting Euclidean patches to the printed slot in the ground plane influence inducing multiple operating bands as similar as multiband fractal antenna, but without using specific formulas or complicated outlines. All proposed antennas have low-profile topologies, good compactness, and more competitive electrical specifications than many reported fractal antennas. The simulations of the proposed printed slot antennas are in good compatibility with the measurements.

This paper discusses the design and simulation of new dual-microstrip antennas using compact resonator topologies and substrates. These antennas were modeled using an applied wave research (AWR) simulator based on quasi-fractal microstrip resonators, a complete ground plane, dual via ports, and FR4 substrate material. The simulated antennas demonstrated multiband responses with tolerable electrical specifications that are suitable for numerous fixed and handheld wireless networks, including WLAN and C bands.

Miniature microstrip diplexer at band frequencies of (1.45/1.95GHz and 2.5/3.5GHz) in two considered channels using the coupled stepped impedance resonators (SIRs) has been presented in this study with mathematical analysis. This diplexer has dual pairs of coupled SIRs with impedance ratio (k>1) and the source-load coupling lines. As a result of the tuning of impedance ratio and length ratio of SIRs, the resonant modes are possibly determined to achieve 2nd order bandpass filter (BPF) with dualband frequency responses for the investigated diplexer. The investigated microstrip diplexer has a simple outline, compact dimensions, an in effect design technique and straightforward calculations of impedance, electrical lengths, fractional bandwidth, coupling factors and other electrical specifications.