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In this paper, we report the results of a preliminary study of the design of dual-band platform-mounted antennas. In this approach, appropriately-designed coupling elements are employed to excite a desired platform mode to obtain an operating band in the HF frequency range. Moreover, the coupling elements are also designed to act as ultra-wideband radiators within the VHF frequency band. The coupling...
Compact and low-profile VHF antennas with enhanced bandwidth have a wide spectrum of applications in both commercial and military communication systems. Having both of these criteria in a single antenna, however, is very challenging. In this paper, we demonstrate a method for bandwidth enhancement of vehicle-mounted electrically-small antennas operating in the VHF band. In this method, the vehicle...
In this study we outline a design process for lumped element implementation of dual-band decoupling network for two coupled antennas. We justify by extensive numerical experimentation that the mutual admittance of the antennas can be transformed to purely imaginary values at two given frequencies simultaneously by very simple transmission line transformers at the antenna inputs. Our study shows that...
This paper investigates a novel multi-segment dielectric resonator antenna (DRA). The antenna consists of a thin segments of different permittivity material bonded to the underside of a rectangular dielectric resonator segment. The multi-segment DRA element is excited by a microstrip line. The permittivity and thickness of the segments are used to concentrate the fields of the micro-scrip line and...
Passive 180° phase-shifters (rat-race or monolithically integrated equivalent) have usually a frequency bandwidth narrower than an octave. A differential amplifier structure provides a very large operating bandwidth, and allows an easy MMIC integration.
The stacked quad EMC super patch with probe feeding was first proposed in [1] and a number of design results for personal communication terminals were provided in [2]. It has wide bandwidth of stacked microstrip antennas and higher gain due to the radiation of subarray. On the other hand, aperture coupling[3] can reduce the interaction between the antenna and feeding network, and the feed can be placed...
Chip based digital isolators are being developed for higher speed and higher isolation capabilities [1, 2]. These make use of various coupling mechanisms such as capacitive coupling [3] and transformer coupling [4]. A limitation of these technologies is that they need to maintain a low separation (distance through insulation DTI<30µm) through high quality insulators (oxides, polyamides) in order...
In this paper, a Full-duplex (FD) antenna system is presented with a high isolation between the TX and RX antennas. The isolation method is based on utilizing balanced antennas to localize the current on the ground plane and single mode excitation of the ground plane with capacitive coupling elements. The simulation results show a promising isolation level of 75 dB. User impact investigation on the...
In this paper, we aim to design a waveguide feeder for a parallel plate slot array antenna for a high resolution Synthetic Aperture Radar system on-board a 100 kg micro-satellite called Micro-XSAR, scheduled to be launched by Japan Aerospace Exploration Agency by 2020. In order to increase the antenna beam-width and thereby mitigate the frequency-dependent beam-shift, we employ center feeding using...
Analog self-interference mitigation techniques are currently being investigated in a variety of operational settings for In-Band Full-Duplex (IBFD) systems. The significant multipath effects of realistic environments, such as inside buildings, can severely limit performance. The influence of different transceiver parameters on the effectiveness of a four-tap RF canceller using a tapped delay line...
This article presents the design of V-band hybrid coupler using new technology i.e. Substrate Integrated Waveguide (SIW) technology. This technology gives suitable components for Millimetre (mm) wave applications. In this hybrid coupler design, the level of reflection and isolation below −20dB occupy more than 2GHz of the bandwidth. The maximum peak occurs at 60GHz with a reflection coefficient of...
Magnetic Induction (MI) is a promising solution for wireless communications in complex environments, such as oil reservoir, underground, indoor, and underwater. Due to the inherent electrically small size and simple structure of the magnetic coil antenna, it suffers from low radiation efficiency, extremely narrow bandwidth, and dramatic polarization loss. Recently, significant efforts have been made...
Filter in telecommunication is a device which has function like a frequency band selector. it plays an significant role especially to select the frequency band that is wanted to be passed through. At this advanced technology era where every device is getting compact in design and size, the filter model also has been challenged in order to meet and fit the recent situation. The microstrip filter is...
Radar detection of fast moving targets at long range, such as ballistic missiles and space objects, poses a significant challenge due to unknown intra-dwell target motion and changes in range-Doppler coupling. This paper describes a new technique to mitigate these problems through the use of a novel waveform and pulse pattern design process which eliminates pulse-to-pulse changes in the received compressed...
NUWC Division Newport has been developing a Low Frequency Range Tracking Transducer (LF RTT) utilizing 2nd generation single crystals operating in the 32-mode to provide tracking pinger transmit capabilities to small-diameter vehicles for which current PZT-based pinger transducers are too large. These transducers reduce the volume and weight by 90% compared to legacy devices while maintaining the...
Two designs of fundamental mode rectangular to circular waveguide TE10 to TE11 mode converter are presented. The waveguide transitions are optimized for operation as an input coupler on a 372 GHz gyro-TWA for Dynamic Nuclear Polarization (DNP) enhancement of NMR imaging. A T-junction input coupler and a multiple hole directional coupler were optimized for operation between 360–384 GHz. The T-junction...
This paper analyzes the influence of state feedback coupling between the capacitor voltage and inductor current in voltage source inverters (VSI) operating in stand-alone microgrids. A decoupling technique is proposed as an effective measure to enhance the dynamics. Further implementation issues and control structures are also considered. Lab-scale experimental results prove the validity of the approaches.
In this paper, an input coupler for W band gyrotron TWT (Traveling Wave Tube) has been designed. This input coupler has the ability of efficiently converts a TE10 rectangular waveguide mode into a TE01 cylindrical waveguide mode. The measured results agree well with the simulated results. With the measured −2dB bandwidth of more than 4GHz, the input coupler can be well used in the experiment of W...
A new approach for designing a parallel coupled-line coupler with controllable bandwidth is presented. The proposed circuit consists of one coupled-line section and four open- or short-circuited stubs tapped at the ends of coupled lines. The adjustable range of fractional bandwidth is from 7% to 45% controlled by adjusting the impedance of stubs. An experiment coupler operating at 2.5 GHz was fabricated...
State feedback coupling between the capacitor voltage and inductor current deteriorates notably the performance during transients of voltage and current regulators in stand-alone systems based on voltage source inverters. A decoupling technique is proposed, considering the limitations introduced by system delays. Laboratory experiments were executed in compliance with the normative for Uninterruptible...
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