Técnicas de aquisição paralelas e hardware dedicados vem sendo desenvolvidos desde a década de 1980 para reduzir o tempo de aquisição de imagens via ressonância magnética (IRM). Uma bobina do tipo phased array é um dispositivo do tipo receptor, que usa múltiplas bobinas (canais) cada qual com seu próprio circuito de detecção para adquirir simultaneamente os sinais que formam uma imagem ou espectro via IRM. Exemplos de técnica de imagem paralela que usa bobinas tipo phased array são Sensitivy Enconding (SENSE) e GeneRalized Autocalibrating Partial Parallel Acquisition (GRAPPA). Sampled array é o nome de um método proposto neste trabalho em que cada canal de uma bobina multicanal é responsável por adquirir de forma independente o sinal da sua amostra de modo que cada sinal de amostra é endereçado ao seu canal específico. Neste trabalho, descrevemos o desenvolvimento de uma bobina phased array de quatro canais para anatomia de cabeça de rato usando circuito impresso flexível para operar em um sistema de IRM pré-clínico de 2T com objetivo de validar o método de construção e uso de circuito flexível como bobina de recepção. Também desenvolvemos uma bobina de quatro canais para realizar simultaneamente a imagem de quatro sementes na mesma varredura para validar o método Sampled Array com objetivo de melhorar a qualidade da imagem e simultaneamente acelerar experimentos de múltiplas amostras. Os resultados mostram que a bobina de circuito impresso phased array, em comparação com uma bobina de enrolamento de fio regular, forneceu uma boa relação sinal / ruído (RSR) e possui geometria mais adequada à anatomia por ser flexível. Além disso, o processo de fabricação da bobina seja facilitado desde que toda a bobina é construída como um protótipo de circuito impresso. Os bons resultados da bobina sampled array mostraram o método como promissor para imageamento de múltiplas amostras com aumento de RSR e diminuição de tempo de experimentos em relação ao uso de bobinas de canal único. / Parallel techniques and dedicated hardware has been developed since the 1980s to reduce acquisition time on Magnetic Resonance Imaging (MRI) scanners. A phased array is a receiver only mode device concept, which uses multiple channels (coils) with their own detection circuits to simultaneously acquire MRI or localized spectroscopic signals. An example of parallel imaging technique that uses phased array coils is Sensitivy Enconding (SENSE). Sampled array is the name proposed in this work for a method in which each channel of a multichannel coil is responsible to acquire independently the signal from its sample so that each sample signal is addressed to its specific channel. In this work, we describe the development of a four-channel phased array coil for rat head anatomy using flexible printed circuit board (PCB), to operate on a 2T pre-clinical MRI scanner to validate the construction method and usage of flexible PCB as a receiver coil. We also developed a four-channel sample array coil to simultaneously perform the imaging of four seeds at the same scan, to validate the proposed method to improve image quality at the same time accelerating multiple seed imaging for agriculture studies. The results show that phased array PCB coil as compared to a regular wire winding coil provide good signal-to-noise ratio (SNR) imaging with more adequate geometry to the anatomy by being flexible. In addition, the coil manufacturing process is facilitated since the entire coil is constructed as a PCB prototype. The sample array imaging showed as a promising method for multiple sample increasing SNR and time to do experiments.

Técnicas de aquisição paralelas e hardware dedicados vem sendo desenvolvidos desde a década de 1980 para reduzir o tempo de aquisição de imagens via ressonância magnética (IRM). Uma bobina do tipo phased array é um dispositivo do tipo receptor, que usa múltiplas bobinas (canais) cada qual com seu próprio circuito de detecção para adquirir simultaneamente os sinais que formam uma imagem ou espectro via IRM. Exemplos de técnica de imagem paralela que usa bobinas tipo phased array são Sensitivy Enconding (SENSE) e GeneRalized Autocalibrating Partial Parallel Acquisition (GRAPPA). Sampled array é o nome de um método proposto neste trabalho em que cada canal de uma bobina multicanal é responsável por adquirir de forma independente o sinal da sua amostra de modo que cada sinal de amostra é endereçado ao seu canal específico. Neste trabalho, descrevemos o desenvolvimento de uma bobina phased array de quatro canais para anatomia de cabeça de rato usando circuito impresso flexível para operar em um sistema de IRM pré-clínico de 2T com objetivo de validar o método de construção e uso de circuito flexível como bobina de recepção. Também desenvolvemos uma bobina de quatro canais para realizar simultaneamente a imagem de quatro sementes na mesma varredura para validar o método Sampled Array com objetivo de melhorar a qualidade da imagem e simultaneamente acelerar experimentos de múltiplas amostras. Os resultados mostram que a bobina de circuito impresso phased array, em comparação com uma bobina de enrolamento de fio regular, forneceu uma boa relação sinal / ruído (RSR) e possui geometria mais adequada à anatomia por ser flexível. Além disso, o processo de fabricação da bobina seja facilitado desde que toda a bobina é construída como um protótipo de circuito impresso. Os bons resultados da bobina sampled array mostraram o método como promissor para imageamento de múltiplas amostras com aumento de RSR e diminuição de tempo de experimentos em relação ao uso de bobinas de canal único. / Parallel techniques and dedicated hardware has been developed since the 1980s to reduce acquisition time on Magnetic Resonance Imaging (MRI) scanners. A phased array is a receiver only mode device concept, which uses multiple channels (coils) with their own detection circuits to simultaneously acquire MRI or localized spectroscopic signals. An example of parallel imaging technique that uses phased array coils is Sensitivy Enconding (SENSE). Sampled array is the name proposed in this work for a method in which each channel of a multichannel coil is responsible to acquire independently the signal from its sample so that each sample signal is addressed to its specific channel. In this work, we describe the development of a four-channel phased array coil for rat head anatomy using flexible printed circuit board (PCB), to operate on a 2T pre-clinical MRI scanner to validate the construction method and usage of flexible PCB as a receiver coil. We also developed a four-channel sample array coil to simultaneously perform the imaging of four seeds at the same scan, to validate the proposed method to improve image quality at the same time accelerating multiple seed imaging for agriculture studies. The results show that phased array PCB coil as compared to a regular wire winding coil provide good signal-to-noise ratio (SNR) imaging with more adequate geometry to the anatomy by being flexible. In addition, the coil manufacturing process is facilitated since the entire coil is constructed as a PCB prototype. The sample array imaging showed as a promising method for multiple sample increasing SNR and time to do experiments.

Creating accurate software based models of phased array feeds (PAFs) is one of many steps to successfully integrating PAFs with current and future radio telescopes, which is a goal of many groups around the globe. This thesis characterizes the latest models of a 19 element hexagonal PAF of dipoles used by the BYU radio astronomy research group and presents comparisons of these models with experimental data obtained using a prototype array. Experiments were performed at the NRAO site in Green Bank, West Virginia, and utilized the outdoor antenna test range and 20 meter radio telescope. Accurate modeling of the PAF requires modeling the signal and noise characteristics of the array, which is a computationally large problem. It also requires accurate modeling of the noise contribution of the receivers connected to the coupled array, which is something that has only recently been understood. The modeled and measured element receive patterns, array impedance matrix, signal and noise correlation matrices, and efficiencies and sensitivities of the PAF are compared and promising levels of agreement are shown. Modeled sensitivity is 30 to 46% larger than measured.

International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / This paper describes a flexible telemetry data link developed by National Nuclear Safety Administration’s Kansas City Plant (NNSA-KCP) and the University of Kansas (KU) in support of NNSA’s Remote Sensing Laboratory (NNSA-RSL) located at the Nevada Test Site. This data link is based on a beam steerable phased array antenna (PAA). The paper describes the PAA and the Airborne Measurement System (AMS) application requiring signal source tracking. It highlights flight test data collected during recent flight testing on the Nevada Test Site for the AMS.

ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California / Direct spatial antenna modulation (DSAM) is a new approach to phased array control that opens up new "smart antenna" architecture possibilities. The DSAM technique leverages the inherent spatial differences of excitation in an antenna in a novel way to achieve the equivalent of conventional modulation and beam control effects. Smart antenna techniques are of potentially increasing importance to test range operations given a trend toward more flexible, internetworked, and autonomous test activities. The DSAM technique has been demonstrated through several generations of analysis, simulation, and prototyping, but has previously only been applied to narrowband antenna designs. Furthermore, the IQ DSAM approach in particular has not been previously implemented in hardware. This paper details the application of IQ DSAM to achieve wideband phase control using a commercial off the shelf (COTS) antenna. The phase control performance of IQ DSAM over a range of 1.5 GHz to 4 GHz is measured across relative field control angles of +/- 45 degrees. The measured IQ DSAM performance is compared to what could be expected from a conventional phased array element control architecture.

ITC/USA 2009 Conference Proceedings / The Forty-Fifth Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2009 / Riviera Hotel & Convention Center, Las Vegas, Nevada / New technologies are sought to meet the requirements of evolving telemetry capabilities such as new operating bands, increased test article and ground segment collaboration, and on-the-fly quality of service (QOS) management. Smart antennas may contribute to this evolution by directing signal energy where and when it is needed. Direct spatial antenna modulation (DSAM) represents a new approach to cost-effective smart antennas potentially offering benefits such as post-amplifier modulation, polarization reconfigurability, phase-shifterless phased arrays, oscillator-less frequency conversion, and pre-receiver processing gain. The basic DSAM approach has recently been proven through analysis, simulation, and prototyping, with significant implications for future capabilities.

International Telemetering Conference Proceedings / October 28-31, 1985 / Riviera Hotel, Las Vegas, Nevada / Military aerospace test ranges are increasingly being called upon to conduct missions utilizing large numbers of participating units, or targets. Precision, position and trajectory data must be recorded on all participants. In addition, weapon/target engagements must be scored and real-time range safety considerations must be accommodated. This requires precision metric data be available in real-time on all participating targets. One solution to these problems, is utilization of multiple target tracking radars which incorporate electronic beam steering to quickly move from one target to another in sequence. This paper briefly recounts the history of range instrumentation radars, points out some of the advantages of using multi-target radars, and highlights the specifications and design of a multiple target instrumentation radar now being acquired by the U.S. Army for use at White Sands Missile Range and the Kwajalein Missile Range.

International Telemetering Conference Proceedings / October 13-16, 1986 / Riviera Hotel, Las Vegas, Nevada / The Airborne Platform Telemetry Relay System (AP/TM) is currently being built for the Gulf Range Instrumentation System. The AP/TM will allow air-to-air missile test and training missions to be conducted beyond the line-of-sight of land-based instrumentation. The AP/TM is comprised of the following subsystems: C a Telemetry Data Relay C a Sea Surveillance Radar and Radar Data Link C a Drone Control Relay C a UHF Radio Relay The Telemetry Data Relay Subsystem will receive telemetry signals from five independent sources and will retransmit them to land based receiving sites. This subsystem contains a 75 square foot, electronically steerable, five beam phased array antenna and uses polarization diversity to eliminate polarization mismatch loss and to improve reception in the presence of multipath propagation. The AP/TM will also have the capability of relaying four channels of voice communications and drone tracking data and to perform sea surveillance of the mission area. The coordinates of targets detected by the radar will be relayed to the range control center over a high frequency (HF) data link. In addition to the airborne equipment, the system also includes a ground support instrumentation van which is used for pre- and post-flight checkout and maintenance.

ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NV / In this work, a 3D-printable multilayer phased array system is designed to demonstrate the applicability of additive manufacturing technique combining dielectric and conductor processes at room temperature for RF systems. Phased array systems normally include feeding networks, antennas, and active components such as switches, phase shifters and amplifiers. To make the integrated system compact, the array system here uses multilayer structure that can fully utilize the 3D space. The vertical interconnections between layers are carefully designed to reduce the loss between layers. Simulated results show good impedance matching and high-directive scanning beam. This multilayer phased array will finally be 3D printed by integrating thermal / ultrasound wire mesh embedding method (for metal) and fused-deposition-modeling technique (for dielectric).

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006. / The design of an electrically small planar antenna for compact circular polarization is presented. After an in-depth study of the performance limitations on electrically small antennas and an investigation into the working of various existing electrically small antennas, the design, simulation and measurement of the proposed antenna element is presented in detail.