The purpose of this work was to make a proposal for input parts of receiver for band 430 to 440 MHz. A model of chosen semiconductor triode BFP540 was created in simulation software. Possibilities how to decrease consumption of this semiconductor triode, keeping the profit, were investigated through the simulation.In compromise consumption, keeping the profit of the amplifier - an optimal operating point for this semiconductor triode UCE = 1,2 V and IC = 2 mA was found. It was tested through the testing wiring with noise microstrips conformity. Ascertained knowledge was used for construction of tuner for UHF receiver. An operating point of input amplifier of UHF receiver was owing to power supply amplifier forced for bigger effectiveness to UCE = 2,65 V and IC = 2,0 mA. Suppression of mirror frequency is provided with Helix filter of the third order, because of intermediate frequency 10,7 MHz. Mixing on intermediate frequency is made again by semiconductor triode BFP540. Selectivity of receiver is provided with intermediate frequency crystal filter 10,7 MHz with bandwidth 15 kHz. Designed input part enables reception of SSB, FM and digital types of modulation.Bandwidth intermediate frequency exit is adapted to this request To receive particular modulation , it is necessary to complete intermediate frequency signal way with appropriate intermediate frequency filter.

This semestral thesis describes RF power amplifier design. In the first section of the work, the possible solutionsand a reflection on the possible solution are presented. In the second section, the principle and thesis for power amplifier design is described. In the third section, the power amplifier design, based on the theoretical knowledge, is described.

This master‘s thesis describes RF power amplifier design. In the first section of the work, the possible solutions and a reflection on the possible solution are presented. In the second section, the principle and thesi for power amplifier design is described. In the third section, the power amplifier design, based on the theoretical knowledge, is described and in fourth section the finaly construction solution and real parameters are described. The last part sumarized the results of this thesis.

abstract: Limited spectral access motivates technologies that adapt to diminishing resources and increasingly cluttered environments. A joint positioning-communications system is designed and implemented on \acf{COTS} hardware. This system enables simultaneous positioning of, and communications between, nodes in a distributed network of base-stations and unmanned aerial systems (UASs). This technology offers extreme ranging precision ($<$ 5 cm) with minimal bandwidth (10 MHz), a secure communications link to protect against cyberattacks, a small form factor that enables integration into numerous platforms, and minimal resource consumption which supports high-density networks. The positioning and communications tasks are performed simultaneously with a single, co-use waveform, which efficiently utilizes limited resources and supports higher user densities. The positioning task uses a cooperative, point-to-point synchronization protocol to estimate the relative position and orientation of all users within the network. The communications task distributes positioning information between users and secures the positioning task against cyberattacks. This high-performance system is enabled by advanced time-of-arrival estimation techniques and a modern phase-accurate distributed coherence synchronization algorithm. This technology may be installed in ground-stations, ground vehicles, unmanned aerial systems, and airborne vehicles, enabling a highly-mobile, re-configurable network with numerous applications. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2019

<p>The recent FDA regulatory clearance for the 7 tesla Magnetic Resonance Imaging (MRI) system has led to increased interest in clinical ultra-high field (UHF) applications. However, to robustly achieve the expected increase in signal-to-noise ratio (SNR) at UHF, the radiofrequency (RF) challenges need to be met, namely, problems with higher RF power, worse <i>B₁⁺</i> inhomogeneity (signal voids) and increased tissue dielectric properties at higher frequency, all of which usually results in increased specific absorption rate (SAR). The parallel transmission (pTx) techniques are generally accepted as a realistic solution, providing improvement in the <i>B₁⁺</i> homogeneity with good RF efficiency while reducing peak local SAR. We designed a hybrid circuit-spatial domain optimization to accelerate the design of a double row pTx head coil. The method predicted consistent coil scattering parameters, component values and <i>B₁⁺</i> field. RF shimming of the calculated field maps matched in vivo performance. To further increase the <i>B₁⁺</i> homogeneity in tissue, we added high dielectric material (HPM) pads near the coil, as the displacement currents in the HPM induced secondary <i>B₁⁺</i> in tissue. This raises a RF safety question of how to monitor millions of local SAR (complex valued Q-matrix) in the tissue voxels, for any weightings (forward voltages) applied to the pTx system. We implemented VOPs based on singular value decomposition to compress the Q-matrices with a compression ratio >100, effectively monitoring the maximum peak local SAR values at given weighting amplitudes.</p>

In a wireless system, the frequency-reconfigurable RF components are highly desired because one such component can replace multiple RF components to reduce the size, cost, and weight. Typically, the reconfigurable RF components are realized using capacitive varactors, PIN diodes, or MEMS switches. Most of these RF switches are expensive, rigid, and need tedious soldering steps, which are not suitable for futuristic flexible and wearable applications. Therefore, there is a need to have a solution for low cost, flexible, and easy to integrate RF switches. All the above-mentioned issues can be alleviated if these switches can be simply printed at the place of interest. In this work, we have demonstrated vanadium dioxide (VO2) based RF switches that have been realized through additive manufacturing technologies (inkjet printing and screen printing), which dramatically brings the cost down to a few cents. Also, no soldering or additional attachment step is required as the switch can be simply printed on the RF component. The printed VO2 switches are configured in two types (shunt configuration and series configuration) where both types have been characterized with two activation mechanisms (thermal activation and electrical activation) up to 40 GHz. The measured insertion loss of 1-3 dB, isolation of 20-30 dB, and switching speed of 400 ns are comparable to other non-printed and expensive RF switches. As an application for the printed VO2 switches, a fully printed frequency reconfigurable filter has also been designed in this work. An open-ended dual-mode resonator with meandered loadings has been co-designed with the VO2 switches, resulting in a compact filter with decent insertion loss of 2.6 dB at both switchable frequency bands (4 GHz and 3.75 GHz). Moreover, the filter is flexible and highly immune to the bending effect, which is essential for wearable applications. Finally, a multi-parameter (switch thickness, width, length, temperature) model has been established using a customized artificial neural network (ANN) to achieve a faster simulation speed. The optimized model’s average error and correlation coefficient are only 0.0003 and 0.9905, respectively, which both indicate the model’s high accuracy.

The multipactor phenomenon is a major concern in modern satellites that operate with highpower transmission in many frequency bands. It occurs when electrons inside RF componentsare accelerated by the RF fields. These electrons then hit walls inside the device, produc-ing secondary electrons. As the number of electrons increases, it may create noise inside thecomponent, thus deteriorating the original signal-to-noise ratio. When designing radio fre-quency equipment for space applications, it is therefore important to know at which powerlevels this occurs. Multicarrier simulations are time consuming and demand high amounts ofcomputer resources. In this thesis the hybrid L1/L2 method has been tested, which is a methodthat separates the geometric and multicarrier simulations into two parts resulting in a shortercomputation time. The conclusion is that the method is more reliable than single carrier sim-ulations, and that it can be used as a first step in the designing process of RF components.It is also a way of estimating a preliminary threshold before starting a full-scale multicarriersimulation.

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Two sources of reniform nematode (Rotylenchulus reniformis) resistance in two Upland cotton (Gossypium hirsutum) developed from related cotton species, BARBREN-713 (Renbarb1 and Renbarb2 genes), and the LONREN germplasm lines (Renlon gene) are available to breeders. Stunting was observed in the LONREN source of resistance, but not for BARBREN. To investigate future use of LONREN germplasm, lines were developed with different combinations of genes from both the LONREN and BARBREN-713 germplasm lines. Marker assisted selection (MAS) was conducted identify these gene combinations within breeding population 1) Renbarb1 +Renbabr2 2) Renbarb1 + Renbar2 + Renlon 3) Renbarb2 + Renlon 4) Renbarb2 5) Renbarb1 6) Renbarb1+Renlon 7) Renlon, and 8) a susceptible genotype. Two populations were identified and increased in 2015. Genotypes were inoculated with 0, 2300, or 5000 reniform nematodes. Seedlings were harvested at 90 days to collect plant measurements and RF of reniform nematodes from roots and soil. The Renbarb1 genotype was susceptible. No significant differences in genotypes were observed for root and shoot measurements, and there was no indication of stunting.