Broadband metasurfaces loaded with non-Foster elements

Metasurfaces have been widely used to design low-profile antennas, thin absorbers, lenses etc. The operational frequency band of a metasurface is rather narrow due to its resonant nature. Loading metasurface unit cells with non-Foster elements allows for remarkable bandwidth extension. In this paper, design of a broadband metasurface to operate as an artificial magnetic conductor is considered. The main issues which influence the bandwidth extension such as implementation of the non-Foster load, minimization of conversion error of a negative impedance converter, and circuit stabilization are addressed.

Design of Wideband Antenna for Millimeter Waves Using HFSS

This paper reviews the objectives and requirements of wideband antenna for millimeter-wave applications using HFSS software (Ansys HFSS V.15.0). In modern era, all wireless devices are multipurpose and versatile, so this requires a wideband antenna to perform different tasks. Microstrip patch antennas are enhancing the performance of communication systems. Patch antennas are becoming more common these days because to their low profile and small weight, making them simple to build. The antenna and propagation issues are further complicated by need for more power, wider bandwidth, stronger gain, and insensitivity to the presence of human users. To provide dependable and interference-free communications and for high-performance millimeter-wave devices need efficient low-profile antennas.

OVERVIEW OF METHODS TO INTEGRATE ANTENNAS AND SOLAR CELLS

Рассматриваются методы проектирования для расширенной интеграции низкопрофильных антенн с солнечными системами для беспроводной связи малого радиуса действия. Необходимость перехода к более устойчивым источникам энергии возникает из-за чрезмерного производства вредных выбросов углерода. Основное внимание уделяется способам интеграции антенн и солнечных панелей из кристаллического кремния. Было предложено решение для минимизации чувствительности, которое использовалось для успешной изоляции микрополосковой линии передачи от солнечной решетки, что позволило продемонстрировать пять конфигураций антенн. Дальнейшая работа над кристаллическими солнечными панелями продемонстрировала их использование вместе с антеннами с круговой поляризацией для летательных аппаратов, а также позволила показать необходимость их использования совместно с Mesh-антеннами для небольших спутников. Солнечная дипольная антенна была разработана для использования внутри помещений с низким энергопотреблением. Эти подходы позволили создать инженерные возможности для уменьшения размера и веса устройства за счет интеграции технологий радио- и солнечных панелей. Представлены основные характеристики антенн для исследуемых случаев, произведено их сравнение, а также определено влияние на их параметры проводниковых материалов The article considers methods for advanced integration of low-profile antennas with solar systems for short-range wireless communications. The need to move to more sustainable energy sources arises from the excessive production of harmful carbon emissions. The focus is on the ways to integrate crystalline silicon antennas and solar panels. We proposed and used a solution to minimize sensitivity to successfully isolate the microstrip transmission line from the solar array, thus demonstrating five antenna configurations. Further work on crystalline solar panels demonstrated their use in conjunction with circularly polarized antennas for aircraft and it also allowed us to show the need for their use with Meshed Patch Antennas for small satellites. A solar dipole antenna was developed for low power indoor applications. These approaches created the engineering capability to reduce device size and weight by integrating radio and solar panel technologies. The article presents the main characteristics of antennas for the cases under study, compares them, and determines the effect of conductive material on their parameters

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.

Configurable Defected Ground Structures for Low Profile Antenna Performance Enhancement

<div>Versatile configurable defected ground structures</div><div>(CDGSs) for enhancing the performance of low profile antennas are introduced. It is shown that CDGS can significantly reduce mutual coupling (MC) between multiple antennas and suppress cross-polarization (XP) and enhance circular polarization (CP) excitation in single port low profile antennas for example. The key idea of CDGS is to construct defected ground structures (DGSs) from a grid of slots, which can be either opened or shorted with hardwires, so that they can be configured and optimized to enhance desired antenna performance characteristics. The</div><div>importance and versatility of the CDGS approach is that it</div><div>overcomes the issue of having to design bespoke DGS for each individual antenna design. Three design examples are provided to demonstrate the versatility of CDGSs for MC reduction, XP suppression and CP excitation. Experimental results demonstrate that MC can be reduced by up to 43 dB, XP can be suppressed by 15 dB and CP can be excited with 78 MHz (2.2%) 3-dB axial ratio (AR) bandwidth. The compactness and ease of fabrication also make the CDGS well suited to compact low profile internet of things (IoT) and wireless communication applications.</div>

Configurable Defected Ground Structures for Low Profile Antenna Performance Enhancement

<div>Versatile configurable defected ground structures</div><div>(CDGSs) for enhancing the performance of low profile antennas are introduced. It is shown that CDGS can significantly reduce mutual coupling (MC) between multiple antennas and suppress cross-polarization (XP) and enhance circular polarization (CP) excitation in single port low profile antennas for example. The key idea of CDGS is to construct defected ground structures (DGSs) from a grid of slots, which can be either opened or shorted with hardwires, so that they can be configured and optimized to enhance desired antenna performance characteristics. The</div><div>importance and versatility of the CDGS approach is that it</div><div>overcomes the issue of having to design bespoke DGS for each individual antenna design. Three design examples are provided to demonstrate the versatility of CDGSs for MC reduction, XP suppression and CP excitation. Experimental results demonstrate that MC can be reduced by up to 43 dB, XP can be suppressed by 15 dB and CP can be excited with 78 MHz (2.2%) 3-dB axial ratio (AR) bandwidth. The compactness and ease of fabrication also make the CDGS well suited to compact low profile internet of things (IoT) and wireless communication applications.</div>

Design and Optimization of Rectangular Patch Antenna Based on FR4, Teflon and Ceramic Substrates

Background: Modern communication devices are very much dependent on the operation of low profile antennas. The objective of this paper is to perform the design and simulation of a rectangular microstrip patch antenna at a resonant frequency of 9.5 GHz. Methods: Design of the antenna is given with various substrates like FR4, Teflon and Ceramic substrates at the desired frequency. For each substrate, the performance of the antenna is measured in terms of its return loss and Voltage Standing Wave Ratio (VSWR). Results: Ansoft High-Frequency Structure Simulator is used to simulate the antenna characteristics. Conclusion: Performance characteristics of the antenna with three different substrates are compared to identify the substrate that provides the accurate return loss and VSWR.

Broadband Stacked Antenna Design with Hybrid Structure for C-band Communication

Two low profile antennas using FR4 and Rogers RT/duroid 5880 as dielectric materials are proposed in this manuscript. To obtain the broadband response the strip-slot hybrid structure is introduced. The two antennas proposed in this manuscript consist of four strips that are segregated through three narrow tapered slots. Using the aperture couple microstrip feed line proper impedance matching is obtained and the slotted patch structure is excited. The simulated bandwidth of 45% is obtained by using the Rogers RT/duroid 5880 as dielectric material with stacked patch structure and gain obtained to be 9.02dB resonating at 4.2GHz of frequency. Proposed design using FR4 as the dielectric material has two resonance frequencies at 4.8GHz and 6.2GHz. The simulated bandwidth of 50% at 4.8GHz and 38.71% at 6.2GHz is obtained with gain of 6.040dB at 4.8GHz. A prototype of the same antenna using the FR4 as dielectric material is also constructed and tested, the tested results shows an impedance bandwidth of 21.87%