Passive Microstrip Transmitarray Lens for Ku Band

The aim of this paper is to introduce a novel 12 GHz radiating design based on the idea of transmitarray lens device. In this document, an overview of the functioning of this kind of devices is given and the proposed transmitarray lens is studied, with architecture discussion and selection, as well as some ideas about the design, and manufacturing. In the document, some design, manufacturing and validation of the constituting elements of the lens (radiating elements, transmission circuits and transitions) are presented, together with a complete prototype of assembled transmitarray lens. Radiation pattern measurements in anechoic chamber, as well as gain and directivity values are offered

Electronically Reconfigurable Patches for Transmit-array Structures at 12GHz

The aim of the paper below is to develop certain active radiating elements for reconfigurable patch arrays. In literature it could be found different possibilities to obtain feasible reconfigurable antennas, whether placing the active circuitry in the transmission lines or directly over the patch. In this paper, the second option is chosen and active radiating elements are analyzed, designed, simulated and prototyped. Finally, measurements of these prototypes are shown. This work is part of a more complete and ambitious project to design and prototype reconfigurable transmit-array structures for microwave applications

Mutual Coupling Reduction Techniques in Electronic Steering Antennas in X Band

This work provides the development of an antenna for satellite communications onboard systems based on the recommendations ITU-R S.580-6 [1] and ITU-R S.465-5 [2]. The antenna consists of printed elements grouped in an array, working in a frequency band from 7.25 up to 8.4 GHz (15% of bandwidth). In this working band, transmission and reception are included simultaneously. The antenna reaches a gain about 31 dBi, has a radiation pattern with a beam width smaller than 10oand dual circular polarization. It has the capability to steer in elevation through a Butler matrix to 4

Circularly polarised broadband planar lightweight reflectarray with eligible pattern for satellite communications in Ku-Band

This study presents a lightweight planar patch-array reflectarray at Ku-band for satellite communications. The reflectarray is composed of two separate planar structures: the radiating interface formed by a planar multi-layered broadband patch array, and a phase shifting device formed by 3 dB/90° couplers. The radiating element is a multi-layered patch structure, designed to provide circular polarisation (CP). Each array cell phase is controlled by open-ended shifting lines of variable length connected to the 3 dB/90° couplers. The use of this kind of couplers maintains the same CP received/transmitted: the design imposes that if a right-hand CP (RHCP) [or left-hand CP (LHCP)] is received coming from the feeder, the same RHCP (or LHCP) configuration is re-radiated by the reflectarray. Additionally, the feeding horn can be moved in the x or y axes, so that the feeder angular position let re-define the radiation pattern and its pointing direction. Finally, measurements of a lightweight portable planar reflectarray prototype are provided and very good agreement is observed when compared with theoretical result

Broadband electronically tunable reflectionbased phase shifter for active-steering microwave reflectarray systems in Ku-band

This document provides the design of an electronically reconfigurable microwave phase shifter for reflectarray systems. The phase shifter is based on a hybrid coupler with reflective circuits in three ports. Each reflective circuit introduces a phase variation that can be modified due to the variable capacity value of a varactor inserted in it. The phase shifting process includes three different stages of phase shifting for the incoming signal in its way through the phase shifter: the signal is conducted through the device towards the reflective circuits in four different ways. The input port of the device is also the output one, providing the desired reflective phase shifting effect. This device is of great interest in reflectarray applications in order to provide more than 360° of controllable phase shifting at each array element. The document includes the complete design of the phase shifter along with its design parameters and circuital behaviour

Diseño, simulación y prototipado de un transmitarray reconfigurable en banda Ku

The aim of this paper is to introduce some theory as well as prototype results of a Ku-band active transmitarray. Its architecture is based in two bi-dimensional radio interfaces interconected by a multiport microwave circuit. This makes the system reconfigurable through a driver device acting on the microwave circuit, which is based in analog phase shifters. The development of the prototypes implies the design of broadband multilayer antenna patches and a novel high-performance reflection analog phase shifte

On the MIMO Capacity for Distributed System under Composite Rayleigh/Rician Fading and Shadowing

Wireless channels are commonly affected by short-term fading and long-term fading (shadowing). The shadowing effects must be taken into account also when mobility is present in the wireless scenario. Using a composite fading model, the total channel capacity can be studied for a scenario with short-term Rayleigh fading along with shadowing. This work provides quantitative results for these kinds of scenarios with Rayleigh fading and shadowing, considering also multiple-input and multiple-output systems, which have not been previously reported. In addition, the channel capacity has been studied in depth in its relation with the shadowing level, signal to noise ratio, and the number of elements in the multiple-input and multiple-output system. Moreover, the channel performance with shadowing has been compared to the one without it. Furthermore, Rician model with shadowing is studied and its results are reported. In addition, correlated and experimental results are provided. It is identified that the distributed MIMO systems can benefit from shadowing in Rician channels. This advantage has not been reported previously. This type of fading is proposed for massive MIMO by others and our results open the door to emulate massive MIMO on a reverberation chamber.This work has been supported by “Gobierno de Extremadura” with project number IB13113, PYR-2014 GENIL project (PYR-2014-CEB09-0010/MICINN), and CEIbioTIC project (mP_TIC_11)

A 1-to-8 Fully Modular Stacked SIW Antenna Array for Millimeter-Wave Applications

This paper presents a vertically stacked SIW antenna array that enables different array configurations with the minimum number of SIW layers. This achievement lies in the modular feature offered by the proposed design. Specifically, 4 distinct array configurations can be produced with only 3 different design of SIW layers. Depending on the number of SIW layers employed in the stacked antenna, the directivity in the E-plane is modified. To obtain an equal and in-phase power distribution among the array elements, H- and E-plane corporate feeding networks are efficiently implemented in each array configuration. Array configurations of 1, 2, 4 and 8 radiating layers are offered by the proposed modular array, where each radiating layer is formed by 8 H-plane horn antennas. The simulated directivity for the array configurations ranges from 15.8 dBi to 23.8 dBi and the main beam direction remains fixed along the operating frequency range. The array design has been manufactured and agreement between simulated and measured results are observed. The measured impedance bandwidth in all the array configurations is from 35 GHz to 41 GHz (15.79% bandwidth) with a reduction in the E-plane beamwidth as the number of radiating layers increases.Spanish GovernmentEuropean Commission PID2020-112545RB-C54 Junta de Andalucia B-TIC-402-UGR18 A-TIC-608-UGR20 P18.RT.4830 PYC20-RE-012-UGR FPU20/00256 FPU18/0196

Electronically reconfigurable reflective phase shifter for circularly polarized reflectarray systems

This letter presents the design of a two-port electronically reconfigurable phase shifter for circularly polarized reflectarray systems at microwave frequencies. The phase shifter is based on 3 dB/90? couplers combined with reflective circuits that introduce sequentially the phase variation. Each reflective circuit, formed by printed elements (L) and tunable varactors, produces the phase variation due to the variable capacity value of the varactor. The phase shifting process includes three different stages of phase shifting for the signal in its way from the input port towards the output port through the phase shifter. Both ports are interchangeable, acting either as input or output ports. This fulfils the reflection requirements of circularly polarized reflectarrays, being especially suitable for this purpose. The complete design, together with its circuital behavior and performance results, are depicted in this document

Glide-Symmetric Pin Phase Shifter implemented in Gap-Waveguide Technology

This paper presents a compact and low-loss waveguide phase shifter based on a pin lattice in glide- symmetric configuration. There is a significant increase in provided phase shift when using a glide-symmetric pin distribution instead of a non-glide-symmetric configuration. A prototype has been manufactured to validate the simulated results of both phase shifters: non-glide-symmetric and glide- symmetric designs. Gap-waveguide technology has been implemented for low-cost manufacturing. The measurement results demonstrate the higher performance and compactness of the glide-symmetric phase shifter. For the same phase shifter length, the glide-symmetric design provides around 80 degrees more of phase shifting compared to the non-glide-symmetric phase shifter. Both phase shifters have a good impedance matching between 46 and 60 GHz (better than -10 dB) and an insertion loss lower than 1 dB.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech