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In this paper a volumetric approach to miniaturizing a 300 MHz loop antenna is presented. Leveraging the benefits of additive manufacturing allows for the antenna to be meandered in a spherical pattern resulting in higher levels of miniaturization while maintaining efficiency. A parametric study provides a design guideline comparing electrical size of the radian sphere (ka) with input impedance. Fabrication...
In this paper, two new Strongly Coupled Magnetic Resonance (SCMR) systems are presented for misalignment study. The efficiency versus azimuth rotation is examined. The analysis is performed using simulations and the results are validated by measurement.
A dual-band dual-mode filter with second order response in each band is presented for application in near-adjacent channel communications systems. Utilizing large perturbations in a meander resonant structure the resonant frequencies of orthogonal field modes are split allowing for a linear coupling arrangement. The filter's passbands are centered at 2.35 GHz and 2.57 GHz with fractional bandwidths...
The use of a sleeve antenna at 10 GHz for microwave ablation is presented. Results for the specific absorption rate (SAR) for the treatment of a 1 cm tumor placed 20 mm from the surface of the liver are presented. To enhance the ablation process, magnetic nanoparticles are introduced in the tumor. Results for the SAR and the temperature profile in the tumor with the nanoparticles are studied. The...
In this paper a lookup table (LUT) based model, suitable for describing the nonlinear behavior of digital radio frequency (RF) power amplifiers (PA), is introduced. Futhermore, the LUT model is compared to nonlinear auto-regressive (ARX) models with respect to performance and computational complexity. This is accomplished by modeling a digital RF transmitter with both techniques and comparing the...
This paper presents a technique for scanning and evaluating the radio spectrum use. This technique determines the average occupancy of a channel over a specific duration. The technique was implemented using Software Defined Radio units and GNU Radio software. The survey was conducted in Grand Forks, North Dakota, over a frequency range of 824 MHz to 5.8 GHz. The results of this technique were compared...
In addition to serve as platforms for dynamic spectrum access, cognitive radios can also serve as a method for improving the performance of wireless communication systems by smartly adjusting their operating parameters according to the environment and requirements. The uncertainty always present in the environment makes the practical implementation of the latter application difficult. In this paper,...
Visible light communication (VLC) is an emerging technology that is expected to be widely used for indoor wireless communications. Accurate localization of VLC equipment has a wide variety of applications in indoor scenarios, where GPS receivers do not work. This paper proposes a new and effective method for localization of VLC devices based solely on the connectivity information. Due to narrow field...
A lumped-element varactor-tuned bandpass filter (BPF) with variable center frequency and constant absolute bandwidth (BW) is presented in this paper. Mixed electric/magnetic inter-resonator coupling schemes—implemented with parallel LC resonators—facilitate the actualization of an almost constant BW passband over a wide frequency tuning range (1.6∶1). The linearity performance of the varactor-tuned...
Fabry-Perot Cavity (FPC) antenna using a single radiating element with different frequency selective surface (FSS) is presented. The FSS designs are rectangular and square unit cells with rectangular and circular openings, respectively. A slot antenna is used as a primary source in the FPC antenna and the system is designed to operate in X-band. The effect of each FSS geometry on the radiation pattern...
A new visualization tool for design is introduced: the Power Smith Tube. It provides aid in designing for optimum power-added efficiency (PAE) while meeting adjacent-channel power ratio (ACPR) requirements. The Power Smith Tube is a three-dimensional cylindrical extension of the Smith Chart with input power as the vertical axis. As such, this Smith Tube allows the visualization of design metrics,...
A one-dimensional, dual frequency, active retrodirective array is proposed. Microstrip circular patch antennas with four shorting pins are used as array elements to suppress surface waves. The proposed design eliminates undesired coupling between array elements due to surface waves present in conventional microstrip antenna arrays in order to improve array performance. The antenna array uses circularly...
This paper reports design techniques for a broadband handset PA with high efficiency using a small-size matching network, serving as a solution to the converged PA module by combining the operation of at least two PAs from the hybrid module into a broader bandwidth. The solution employs class-J to achieve higher efficiency and broader bandwidth, combined with a new design technique for lumped matching...
This paper discusses the mechanical vibration effect of metal structure on RFID and presents a solution to circumvent it. The transmission link between a tag and RFID reader is affected by induced current issued from magnetic coupling. This interference affects mainly the performances of the RFID reader. A new practical technique that avoids the resulting coupling interference is presented in this...
In this paper a reliable and cost-effective modeling approach for GaN HEMT on both Si and SiC substrates is presented. The developed model is validated in terms of small-and large-signal simulations for 2-mm GaN-on-Si and 1-mm GaN-on-SiC HEMTs.
In this paper we would like to point out one open issue related with filtered bank multi-carrier signals (FBMC). The experiment was trying to give an answer whether the FBMC signals would keep their beneficial properties even whilst real non-linear power amplifiers were employed. As one of the merits that have been used were error vector magnitude (EVM) and adjacent channel power (ACP). Due to higher...
This paper represents design of Substrate integrated waveguide (SIW) based bandpass filters for the centre frequency of 22.5 GHz and 23.5 GHz for communication between two satellites. A proposed filter has been designed for the transceiver used in communication linking and ranging between two satellites. However, the allotted band for satellites communication is 22.5–23.5GHz so that we have to design...
A microwave planar interdigital capacitor (IDC) based resonator etched on the central conductor of a coplanar waveguide (CPW) structure is presented to measure the complex permittivity of common solvents. The proposed structure is working as a resonator with the resonant frequency of 6.5 GHz under unloaded condition. A sample holder made of borosilicate glass is especially designed to contain the...
In this paper, we discuss layout problems encountered in power amplifiers with negative parallel feedback. We show how to reduce the risk of an unstable power amplifier (PA) by careful layouting without the use of additional elements and thus chip area. Optimised vs. non-optimised layouting are compared and verified with fabricated ICs. Finally a PA with large signal bandwidth of 1.9 GHz at a design...
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