AWE-Inspiring Electrically Small Antennas

Anytime-wireless-everywhere (AWE) aspirations for Internet-of-Things (IoT) applications to be enabled through current 5G and evolving 6G and beyond ecosystems necessitate the development of innovative electrically small antennas (ESAs). While a variety of ESA systems are reviewed, those realized from the near-field resonant parasitic (NFRP) antenna paradigm are emphasized. Efficiency, bandwidth and directivity issues are highlighted. Multifunctional, reconfigurable, passive and active systems that have been achieved are discussed and illustrated; their performance characteristics and advantages described. This overview finalizes by going back to the future and considers enterprising research areas of current and forward-looking interest.

Arrays of electrically small antennas with SINIS detectors for SubTHz astronomy and atmosphere propagation research

An overview of different arrays of electrically small annular antennas of 350 GHz band with integrated superconductor-insulator-normal metal-insulator-superconductor (SINIS) detectors is presented in this paper. Arrays developed for both astronomical observations on the BTA 6 m telescope and measurements there of test sources for investigation of atmospheric turbulence to estimate its influence on the data rate of subTHz telecommunication channels. It is shown both numerically and experimentally that to simulate the electrodynamics of such non-phased antenna arrays it is necessary to investigate the whole array, not a single cell with Floquet ports. The first results of studying of superconducting antennas are also presented in this paper.

Innovative Design and Analysis of an Electrically Small Reconfigurable Antenna for GPS and Blue Tooth Applications

In this paper, an electrically small, planar antenna with broad side radiation pattern is presented. The design contains a dipole and a segmented circular loop which works equivalent to that of a magnetic dipole. A circular patch with slots is used to provide impedance matching. In general, electrically small antennas suffer from narrow bandwidth. In this paper, the reconfigurability of the small antenna for two different applications, 1.5GHz and 2.4GHz, is discussed. This reconfigurability was achieved by using a BAR 64-03W pin diode to adjust the resonant frequency. Two reconfigurable frequency bands were achieved at 1.5GHz and 2.4GHz with broad side radiation patterns.

On the Effects of Balun on Small Antennas Performance for Animal Health- Monitoring and Tracking

This paper presents the performance evaluation of a sleeve Balun integration in the design of a flexible loop antenna for wildlife health monitoring and tracking applications. To verify the design concept, an experimental antenna is designed, fabricated, and measured in free-space and muscle mimicking phantom. Moreover, investigations are carried out for wearable and implanted antennas in planar and conformal arrangements. In free-space, the antenna is operating within the industrial, scientific, and medical ISM 5.8 GHz band. Balun integration in the antenna design efficiently chokes the currents excited on the outer surface of the feeding cable and provides a good impedance match between antenna and feed line, as demonstrated by simulation and measurement results. On the other hand, in phantom, the antenna has a wide bandwidth characteristic that covers the most used frequency bands for in-body devices. Balun integration, in this case, showed a negligible effect on antenna’s matching properties for two studied implantation depths; 2.5 cm and 5 cm. The proposed study offers a promising guideline in the design and realization of wearable and implanted antennas.

Metamaterial-inspired electrically small antenna for microwave applications

Electrically small antennas are becoming more important to compete with the rising modern civilization. Hence, this study presents a new approach of electrically small antenna inspired by a metamaterial structure which creates an impact by achieving a multi-band property that can be applied for different microwave applications. A high-frequency electromagnetic simulator was utilized to design, simulate, and analyze the antenna performance. About 58% reduction was achieved due to the incorporation of the modified electric field-driven capacitor-driven metamaterial. The initial length of the antenna was 0.61λ0 × 0.58λ0 × 0.12λ0; however, after embedding metamaterial, 58% reduction was achieved and the size of the electrical length of the reduced antenna becomes 0.254λ0 × 0.207λ0 × 0.013λ0, where λ0 denotes free-space wavelength. The electrical limitation factor (ka) of the antenna that was 0.94 (below 1) satisfied the conditions of electrically small antenna. The antenna achieved the highest measured gain of 4.79 dB. Due to its compact miniaturized size and resonance characteristics, the proposed antenna is compatible for broad spectrum of applications in the field of microwave communication.

DESIGNING A REFLECTION-TYPE NGD NETWORK USING OPEN AND SHORT SHUNT STUBS FOR WIDEBAND ELECTRICALLY SMALL ANTENNAS

Wireless communication devices such as mobile phones play a vital role in our daily life. They need to cover an increasingly wide frequency band with low profile antennas. Electrically small antennas (ESAs) comply with these requirements. However, they are subject to gain-bandwidth limits when matched with passive matching networks. Non-Foster reactive elements have been proposed to bypass those restrictions. This paper addresses designing negative group delay NGD-based non-Foster networks to overcome stability problems when using Negative Impedance Converters (NICs) in order to realise on-Foster reactive circuits. The NGD network model was designed using open short stubs to achieve a non-Foster behaviour, and to act as a negative capacitor in the frequency range of interest. This technique of compensating the inherent loss of the proposed NGD network in the reflection mode was to realise a new structure of reactive non-Foster elements. It involves a negative resistance amplifier and a Lange coupler. The proposed technique is applicable to antenna matching where both transmit and received capabilities are required. It was simulated and the experimental results of the new NGD network circuit were introduced.