A5024542840- Microwave Engineering and Waveguides
- Antenna Design and Analysis
- Advanced Antenna and Metasurface Technologies
- Full-Duplex Wireless Communications
- Antenna Design and Optimization
- Radio Frequency Integrated Circuit Design
- Particle Accelerators and Free-Electron Lasers
- Millimeter-Wave Propagation and Modeling
- Advanced Power Amplifier Design
- Semiconductor Lasers and Optical Devices
- Particle accelerators and beam dynamics
- Wireless Communication Networks Research
- Gyrotron and Vacuum Electronics Research
- Advanced Materials and Mechanics
Johns Hopkins University Applied Physics Laboratory
2023
Johns Hopkins University
2023
University of Central Florida
2015-2020
Los Alamos National Laboratory
2002
A third-order substrate integrated waveguide (SIW) filter/antenna is presented in this letter. The composed of two cavity resonators with a slot antenna the second cavity. excites modes cavity, creating filtering response while preserving radiating characteristics. transmission zero can be arbitrarily placed below or above passband. operates at center frequency 3.71 GHz and has an 8.29% fractional bandwidth 5.10 dBi gain.
In this article, a 7×7 reconfigurable reflectarray operating at X- band is proposed and experimentally verified. The consists of linearly polarized, dual-resonance, tunable unit cells fabricated on single layer. Reconfigurability achieved by loading each dual-resonance cell with four varactors; the two resonances provide phase range greater than 360°. design utilized in analyzed using full-wave Floquet simulations. A biasing network supporting individual array element designed, allowing...
In this research, a novel method of phased antenna array beamforming using convolutional neural network is presented. Given desired 2-dimensional radiation pattern, the calculates phases required to synthesize pattern and capable synthesizing complex patterns. The trained an 8×8 microstrip patch accuracy confirmed with simulations.
In this article, tunable integrated filter/antennas are demonstrated with two coupling configurations that provide design control of the bandwidth performance over tuning range. The first is a single-layer third-order filter/antenna an increasing fractional (FBW). measured device has frequency range from 1.62 to 2.08 GHz, FBW 3.0% 4.8%, and gain -7.3 3.6 dBi. second double-layer vertically provides constant absolute This accounts for frequency-dependent behavior antenna radiation Q. 1.65...
A new class of phase shifter based on a bandpass filter with reconfigurable transmission zeros is presented in this work. By using tunable resonators that are extracted from the main signal path, shift obtained minimal effect insertion loss tuning elements. total range 120 degrees measured maximum figure merit 80 degrees/dB. study coupling matrix forms basis and measurements simulations agree well theory. Additional can be by adding additional without impacting loss.
An electrically tunable planar hairpin filter integrated with a microstrip patch antenna is proposed in this paper. The as resonator, contributing to second-order filter. integration performed eliminate 50-ohm transition losses and reduce the overall structure size. magnetically coupled resonator operates at center frequency of 3.03 GHz fractional bandwidth 2.38%. gain 5.41 dBi. Electrical tuning ability provided via four varactors response range from 2.77 3.19 GHz.
A high-Q 3-D filter/antenna integration is presented herein. The composed of a surface gap ring resonator and cavity-backed slot antenna, where the antenna has narrower bandwidth than filter causing it to behave as contribute pole filtering function. operates at center frequency 3.75 GHz with fractional 8.07%, gain 4.94 dBi, overall efficiency 95.4%.
A tunable 3-D filter/antenna integration implementation is presented herein. The integrated device consists of a coaxial substrate waveguide (SIW) resonator coupled to cavity-backed slot antenna. synthesis in this work follows closely with traditional filter the antenna coupling energy free space used as second external port device. frequency from 1.71-2.88 GHz (51%) fractional bandwidth range 2.90-8.10%, gain -3.14-2.61 dBi, overall efficiency between 26.3 and 82.6%, cross polarization...
This paper presents a novel co-designed Doherty power amplifier (DPA) and post-matching output bandpass filter. The filter is designed as matching network to present the desired impedance at combining node of carrier peaking paths, thus eliminating quarter-wave transformer conventional combiner network. co-design method minimizes circuit complexity inter-connection loss, leading an enhanced overall performance. A prototype implemented using GaN transistors third-order Hairpin with 20%...
We have designed and are building a subpicosecond electron injector. The injector is based on an 8 MeV photoinjector, used previously at Los Alamos in the APEX experiment. nominal design includes magnetically compressing 20 ps long, 3 nC bunch to FWHM length of 2/3 (peak current excess kA) using four dipole chicane buncher. geometrical averaged transverse normalized emittance after compression about 15 /spl pi/ mm mrad.
This paper presents a vertically-integrated second-order tunable planar filter/antenna that expands upon previous work with filter/antennas. demonstrates the use of radiating element as resonator in filter and uses mixed electric magnetic coupling to achieve constant absolute bandwidth over tuning range without need additional elements on structures. The device is from 1.65 1.95 GHz an 52.03 ± 2.76 MHz return loss above 15 dB range. measured gain -0.52-5.72 dBi cross-polarization level...
A symmetric radial filtering power divider is presented herein. The implemented in a substrate integrated waveguide (SIW) and designed using filter theory to obtain equal 6-way division with function each port. filter/power operates at center frequency of 11.53 GHz fractional bandwidth 37.2%, insertion loss 8.44 dB port, worst-case isolation 9 between ports.
A fully integrated 1×4 filtering linear antenna array is presented in this work. The designed substrate waveguide technology and consists of 5 coupled cavities with a 6 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> -order function. formed arrangement four slot antennas the final which excite two modes radiating cavity. operates at center frequency 6.75 GHz fractional bandwidth 5.0% gain 7.44 dBi.