A Curved Microstrip Patch Antenna Designed From Transparent Conductive Films

Transparent microstrip patch antennas suffer from low radiation efficiency and gain when manufactured using transparent conductive films (TCFs), mainly at low frequency (starting from the microwave S band). To address this problem, we propose a curved microstrip patch antenna designed using transparent materials. This new configuration has proven to be a simple and effective solution to improve the radiation efficiency and gain of TCF printed antennas. In fact, when typical values of the TCF surface resistance are considered (between 2 and 10 Ω/sq), the new antenna features a radiation efficiency of up to 72.3% and a realized gain of up to 5.3 dBi at 2.15 GHz, with a significant improvement in comparison with the flat transparent microstrip antenna (up to 17.7% radiation efficiency, and 0.5 dBi realized gain). Good transparency and lightweight is ensured by the deposition of the TCF on a polyethylene terephthalate film, which lies, in turn, on a 3D-printed curved polyethylene terephthalate glycol supporting frame. Simulations using Ansys HFSS are presented to demonstrate the potential of the proposed configuration. Then, a prototype of the transparent curved patch antenna is fabricated and measured to assess the simulated results

Разборная отражательная антенная решетка Ku-диапазона частот на основе микрополоскового элемента в виде мальтийского креста

Introduction. Reflectarrays have a number of design and functional advantages over their closest analogue - reflector antennas (RA). Although microstrip elements are the most preferred reflectarray elements, single-layer microstrip elements do not allow accurate phase control due to the limited phase adjustment range and a high phase slope. The use of multilayer elements significantly complicates the antenna design and increases its cost. The development of a single-layer element that allows more than 360° phase adjustment and a low phase curve slope is urgent.Aim. To develop a single-layer microstrip phase-correcting element with a phase adjustment range of more than 360° and to design a reflectarray on its basis for operation in satellite communication networks.Materials and methods. Numerical studies were carried out using finite element analysis and the finite-difference time-domain method. Radiation patterns were measured using the near-field scanning method in an anechoic chamber.Results. A phase-correcting element based on a single-layer Maltese cross-shaped microstrip element with close to linear dependence of element size on the phase of the reradiated wave and more than 360° phase adjustment range was developed. On the basis of the investigated element, a foldable reflectarray was designed. The reflector consists of four subarrays, which provide its compact folding for transportation. The results of experimental studies confirmed a high efficiency of the reflectarray, the gain of which is 1.5 dB lower than that of an identical overall dimensions RA in a 7 % operating frequency band. The operating frequency band of the reflectarray in 1 dB gain zone was 11 %.Conclusion. On the basis of a Maltese cross microstrip element, it is possible to implement a single-layer reflectarray with a more than 10 % frequency band. The developed prototype showed the possibility of creating highly efficient foldable reflectarrays for operation in satellite communication and television terminals.Введение. Отражательные антенные решетки (ОАР) обладают рядом конструктивных и функциональных преимуществ относительно ближайшего аналога – зеркальных антенн (ЗА). Наиболее предпочтительными элементами ОАР являются микрополосковые, однако однослойные микрополосковые элементы зачастую не позволяют точно скорректировать фазу в ОАР из-за ограниченного диапазона фазовой регулировки и высокой крутизны фазовой кривой. Использование многослойных элементов заметно усложняет и удорожает конструкцию антенны. В связи с этим актуален поиск однослойных элементов, обеспечивающих фазовую регулировку более 360° с малой крутизной фазовой кривой.Цель работы. Разработка однослойного микрополоскового фазокорректирующего элемента отражательного типа с диапазоном регулировки более 360° и создание на его основе ОАР для работы в сетях спутниковой связи.Материалы и методы. Численные исследования проведены методом конечных элементов и методом конечных разностей во временно́й области. Характеристики направленности измерялись сканированием ближнего поля в безэховой камере.Результаты. Разработан фазокорректирующий элемент на основе однослойного микрополоскового резонатора в виде мальтийского креста с близкой к линейной зависимостью фазы отраженной волны от размера элемента, обеспечивающий диапазон фазовой регулировки более 360°. На основе исследованного элемента разработана и изготовлена разборная конструкция ОАР, в которой рефлектор состоит из четырех подрешеток, что обеспечивает компактное свертывание ОАР для транспортировки. Результаты экспериментальных исследований показали высокую эффективность ОАР, коэффициент усиления (КУ) которой на 1.5 дБ ниже КУ ЗА идентичных габаритных размеров в относительной полосе рабочих частот (ОПРЧ) 7 %. ОПРЧ ОАР по уровню снижения КУ на 1 дБ составила 11 %.Заключение. На основе элемента в виде мальтийского креста возможна реализация однослойных ОАР с ОПРЧ более 10 %. Разработанный макет показал возможность создания высокоэффективных сворачиваемых ОАР для работы в составе терминалов спутниковой связи и телевидения

Design and development of dual-Polarised photovoltaic solar antennae for Ku-band SatComsp.

The aim of this thesis is to review the state-of-the-art of transparent patch antennae and to develop design techniques for the experimental development of dual-band, dual-polarised compact transparent patch antennae integrated with solar cells for Ku-band satellite applications. It can be specifically used for Fixed-Satellite-Services (FSS) operating over the frequency range from 11.7 GHz to 12.22 GHz (downlink) and 14.0 GHz to 14.5 GHz (uplink) bands. The research reported in this thesis demonstrated a suspended meshed patch antennae serves as a basic building-block element for a Ku-band dual-polarised transparent array antennae for long distance communications. The results are shown that the use of a suspended patch above a printed radiating patch and ground plane (all transparent) provides dual-band operation for the uplink and downlink. In this work, firstly, a compact low-profile linearly polarised meshed element has been designed, and simulated in CST Microwave Studio electromagnetic simulation software. The photovoltaic antennae element was then fabricated and measured. The comparison between the experimental results and simulation by CST demonstrates good agreement between predicted and practical measurements. The developed antennae element achieved the overall broad bandwidth of more than 1GHz (500 MHz in each of the uplink and downlink bands), and the nominal element gain is 6.055 dBi (downlink) and 7.61 dBi (uplink). A good compromise between the RF performance and the transparency is also obtained with optical transparency of 84% and negligible degradation of the RF performance. The design is then extended to develop a Ku-band photovoltaic antennae element for dualpolarised operation This element could be used for frequency re-use in Ku-band satellite downlink and uplink communicationsin order to double capacity. In addition, the simulation of a 2 x2 sub-array of dual polarised transparent antennae elements (using the experimentally measured performance of the single dual-polarised element) is presented. It has yielded a narrow beam with increased gain of 13 dBi and a cross-polar discrimination of greater than 30 dB is demonstrated, which is a requirement for frequency re-use operation. Hence, the dual-polarised 4-element sub-array described herein could be utilised as the primary building block for a 2D SatCom phased array antennae. In order to meet the full requirements of Kuband SatCom communications employing frequency re-use which essentially doubles the achievable capacity, i.e. two data channels can use the same frequency bands simultaneously using the two orthogonal polarisations with high cross-polar isolation. Using these new designs providing new knowledge in the field of photovoltaic communication antennae at high frequencies, and bridge the associated drawbacks with the current PV antennae