Rectangular Output Research Articles

Broadband Rectangular Waveguide TE10–TE20 Mode Converter With In-Line Ports and Compact Structure

This letter presents a compact and broadband TE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{10}$</tex-math> </inline-formula> –TE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{20}$</tex-math> </inline-formula> mode converter for millimeter-wave and terahertz applications. The input rectangular waveguide (RWG) and output over-mode waveguide (OMWG) are in-line and orthogonal in arrangement. In this converter, the waveguide mode is converted in the short height-reduced and width-widened gradient waveguides. A simple cuboid matching structure is employed to improve bandwidth and conversion efficiency, and a bed of nails is applied to the waveguide profile to suppress electromagnetic (EM) leakage and facilitate assembly at high frequencies. For further verification, a pair of WR-4.3 band prototypes were fabricated and measured. In the range of 170–252 GHz (38.9%-bandwidth), the measured insertion loss of the back-to-back converters is found to be around 0.86 dB with the worst return loss of 14 dB except for a slight deterioration at 172 GHz. Deducting the waveguide insertion loss, the conversion efficiency is higher than 98%.

EXPERIMENTAL EVALUATION OF THE HOMOGENEITY OF THE OUTPUT STREAMS OF OPTICAL RADIATION OF A RECTANGULAR SHAPE FOR VARIOUS VERSIONS OF THE OUTPUT SECTIONS OF THE LIGHT GUIDE NOZZLES FOR MEDICAL LASER EQUIPMENT

The article presents the results of a study of the homogeneity of rectangular optical radiation fluxes for different versions of the initial sections of the light guide nozzles. When conducting a significant part of laser exposure in medicine, pathological areas of biological tissue or their projections located on the surface of the body are covered with light spots with contours, as a rule, in the form of flat geometric shapes.&#x0D; The variability of the implementation of light spots in shape (circle, square, rectangle, triangle, rhombus, etc.) and linear dimensions of the cross section allows you to select the shape and size of the light spot, covering a specific pathological surface with minimal capture of intact tissues. At the same time, regardless of the shape and linear dimensions, the light spots should be as uniform as possible. To date, of particular interest is the provision of optical uniformity of rectangular light spots.&#x0D; Firstly, similar forms of spots are widely used under the influence of laser medicine. Secondly, in the original optical stages of laser equipment and the light guides connected to them, first of all, optical fibers of a cylindrical shape with a rounded cross section of the optical flow at the output are used. The purpose of this work is to optimize the parameters of light guide nozzles of medical laser equipment with rectangular output optical radiation fluxes by evaluating the uniformity of the power density distribution for various options for the output sections of the nozzles. In the work, optical flows at the output of three versions of the distal sections of light guides were studied. The light guides were formed by optical fibers, including the use of microlenses at the output ends, and were apertured by channel optical waveguides in the form of rectangular parallelepipeds.&#x0D; The experimental results obtained at the stage of physical modeling show the promise of using spherical micro-optical elements at the initial ends of optical fibers in combination with rectangular apertures in the form of channel optical waves to obtain rectangular light spots with a high level of optical homogeneity.

Extending the EclipseTM AcurosXB output factor table for small field radiosurgery.

To investigate the necessity of extending the output factor table (OF Table) of the Varian EclipseTM Treatment Planning System for small field stereotactic radiosurgery (SRS) and stereotactic body radiosurgery (SBRT) treatments. A new AcurosXB 15.6 beam model was created in the Eclipse Beam Configuration, which is identical to the one that has been used in the clinic with a default 3×3cm to 40×40cm OF Table, except the OF Table in the new model was extended to cover the range from 1×1cm to 40×40cm. 80 small square and rectangular output factors were measured on a Varian TrueBeam utilizing a Standard Imaging Exradin W2-1×1 scintillator detector, inside a PTW BeamScan water tank with 95cm SSD at 5cm depth. Cerenkov contamination was corrected using a rectangular field method (2cm×15cm field). Nine Radiosurgery plans with primary jaw setting ranging from 0.7cm to 2.0cm were evaluated by both beam models. The monitor unit (MU) differences between the two beam models were calculated for identical 3-dimensional (3D) absolute dose distributions. Output factors, measured versus Eclipse calculated, were compared down to 0.5×0.5cm primary jaw setting. For the 6FFF beam, the difference between the two beam models was ∼ 6% for 1×1cm jaw settings and 4% at 1.5×1.5cm, with the extended OF Table requiring higher MUs for the same dose prescription and same 3-dimensional isodose distribution. For the 6MV beam, the corresponding difference is ∼7.5% for 1×1cm, 5% for 1.5×1.5cm, and 3% for 2×2cm jaw settings, with the extended OF Table requiring higher MUs. For jaw settings smaller than 1×1cm, measured dose can be considerably smaller than Eclipse predicted dose, even with the OF Table extension. This is reflected by the fact that the output factor for 0.5×0.5cm, calculated via Eclipse external beam, was more than 30% greater than that measured for both 6FFF and 6MV beams. Eclipse does a satisfactory job for primary jaw sizes down to 2cm. For jaw settings smaller than 1.5cm, the OF Table in Eclipse should be extended to improve the dose calculation accuracy.

Generation of cylindrical vector dissipative soliton using an ultra-broadband LPFG mode converter with flat conversion efficiency

Dissipative solitons (DSs), which are pulses with high pulse energy and a broad rectangular output spectrum, have several applications. In a fiber system, the generation of higher-order DS requires a mode converter with a high and flat conversion efficiency that can cover the working waveband. The requirements on high and flat conversion efficiency as well as broadband working waveband is a great challenge for a traditional mode converter. This study presents an L-band mode-locked fiber laser with a 3-dB bandwidth of more than 47 nm and a first-order cylindrical vector (CV) mode DS output based on an ultra-broadband long-period fiber grating (LPFG). The fabricated mode converter is a novel cascading LPFG with an ultra-broadband working bandwidth and flat conversion efficiency which could meet the demand of DS mode conversion. The 15-dB bandwidth is 149.76 nm, from 1515.36 nm to 1665.12 nm. Furthermore, the conversion efficiency in the range of the output spectrum is 98.60 ± 0.23%. The single-, double-, and triple-soliton output characteristics and their real-time spectra are observed using time-stretched dispersion Fourier transformation (TS-DFT) technology. Experimental results demonstrate that the first-order CV mode DS laser can maintain its dynamics after mode conversion under the accuracy of detection system, implying that the LPFG works only as a mode converter. The broadband DS laser with CV mode output in the L-band has been presented for the first time in study, to the best of our knowledge. This study is also the first to detect real-time characteristics for a higher-order mode-locked fiber laser using the TS-DFT technology. The proposed type of LPFG is s good candidate for generating higher-order mode lasers with an all-fiber structure.

All-solid-state bipolar pulsed generator based on linear transformer driver and push-pull circuit.

All-solid-state linear transformer drivers (LTDs) are widely used in high-voltage repetitive nanosecond-pulsed generators, and only a few LTD generators can output bipolar rectangular waves currently. Furthermore, owing to the large reverse overshoot when the output pulse width is long, fewer LTD generators can achieve a rectangular wave output with a microsecond pulse width. In this study, a bipolar LTD circuit topology based on a push-pull circuit is proposed for irreversible electroporation. In this topology, a single-stage LTD module has four push-pull branches in its primary winding to achieve a bipolar output and a short-circuited winding with two resistor-capacitor-diode snubbers to suppress forward/reverse overshoot. A single-stage LTD module and a 12-stage LTD have been tested, and the results show that they can output bipolar rectangular pulses with variable parameters. When the output pulse width is 100ns to 1 µs, the maximum output voltage amplitude is 5.74 kV, the rise time is 29.1ns, and the reverse overshoot at 1 µs is 2.9%. When the output pulse width is 1-8 µs, the maximum output voltage amplitude is 2.93 kV, the rise time is 24.3ns, and the reverse overshoot at 8 µs is 11.3%.

Chemical Reactions-Based Microfluidic Transmitter and Receiver Design for Molecular Communication

The design of communication systems capable of processing and exchanging information through molecules and chemical processes is a rapidly growing interdisciplinary field, which holds the promise to revolutionize how we realize computing and communication devices. While molecular communication (MC) theory has had major developments in recent years, more practical aspects in designing components capable of MC functionalities remain less explored. This paper designs chemical reactions-based microfluidic devices to realize binary concentration shift keying (BCSK) modulation and demodulation functionalities. Considering existing MC literature on information transmission via molecular pulse modulation, we propose a microfluidic MC transmitter design, which is capable of generating continuously predefined pulse-shaped molecular concentrations upon rectangular triggering signals to achieve the modulation function. We further design a microfluidic MC receiver capable of demodulating a received signal to a rectangular output signal using a thresholding reaction and an amplifying reaction. Our chemical reactions-based microfluidic molecular communication system is reproducible and its parameters can be optimized. More importantly, it overcomes the slow-speed, unreliability, and non-scalability of biological processes in cells. To reveal design insights, we also derive the theoretical signal responses for our designed microfluidic transmitter and receiver, which further facilitate the transmitter design optimization. Our theoretical results are validated via simulations performed through the COMSOL Multiphysics finite element solver. We demonstrate the predefined nature of the generated pulse and the demodulated rectangular signal together with their dependence on design parameters.

A New 4 × 4 Rectangular Waveguide Short-Slot Coupler in 3D Printed Technology at Ku-Band

This paper presents a novel design of an eight-port directional coupler with a very compact structure and simple manufacturing, working in the Ku frequency band. One of the main goals of the design was to ease the manufacturing with a simple structure: the coupler consisted of four rectangular waveguide input ports, four rectangular waveguide output ports, and a central coupling region with only H-plane variation. A prototype was fabricated using additive manufacturing, with a combination of 3D printing and silver coating metallization. The obtained performance showed a theoretical bandwidth of 6.6% with 20 dB return loss for the input/output ports. Good agreement between simulations and measurements was obtained, validating the proposed coupler as a good trade-off for low cost 3D printing, compactness, and high performance for systems requiring a high number of ports as in phase arrays or Butler matrices.

Highly Integrated Resonant Tunneling Diode with Rectangular Waveguide Output for W-Band Communication System

A packaged resonant tunneling diode (RTD) with rectangular waveguide output for highly integrated wireless communication is proposed. The output signal of the RTD chip is radiated to the rectangular waveguide through an E plane probe transformer. Next, the RTD chip is electrically connected to the transformer by using gold wire bonding. The packaged RTD exhibits an oscillation frequency of 92 GHz, while the maximum radio frequency (RF) output power is −7 dBm. A miniaturized and high data rate wireless communication system with a 7 Gbps on–off keying (OOK) module by using the RTD is demonstrated, and the bit error rate (BER) of the 7 Gbps is below 3.8 × 10−3.

Piezoelectric Micropump Driving Module with Programmable Slew-Rate and Dead-Time

High efficiency piezoelectric micropump driving module with programmable slew-rate and dead-time has been designed, implemented and characterized for driving custom made piezoelectric micropumps. Developed driver enables independent setting of several rectangular output signal parameters, such as frequency, positive and negative amplitudes, slew-rates, dead time, and modes of operation (pump/valve). Implemented driver can achieve amplitudes up to 250 V PP on a frequency range from DC to 1 kHz, slew-rate up to 18V/μs at maximum power consumption 1.6 W (180 mA @ 9 V). In comparison with our previous driver with RC charge/discharge signal shape, presented version increases air flow capability of micropumps from 1.6 sccm to 4.2 sccm. It enables driving of 200 μm thick PZT actuators with 12 nF capacitance.

Assessing the Efficiency of a Stokes Polarimeter with Different Polarization Analyzers

Polarimetric studies in astronomy have currently acquired great importance. They are used to study magnetic fields of stars, determine the orientation of orbits of exoplanets, reflection effects in stellar atmospheres and accretion disks, and many other things. This paper presents a computation of optical arrangements of Stokes polarimeters with different polarization analyzers. A preliminary estimate of the transmission of polarimeters with a Wollastone prism and with a modified Foster prism as polarization analyzers is reported. Transmission estimates were performed for different shapes of rectangular output slits and separations between them in two spectral ranges. Recommendations are provided concerning the use of Wollastone and Foster prisms in Stokes polarimeters designed for astrophysical studies.

Rectangular Pulse Generation From a Mode Locked Raman Fiber Laser

Rectangular and step-like pulses are generated in a mode-locked Raman fiber laser with a nonlinear optical loop mirror. The Raman laser has a typical figure-8 configuration. Stable rectangular pulses with a fundamental repetition rate of 733 kHz are obtained. As the pump power increases, the Raman pulse evolves to a step-like rectangular pulse. The maximum pulse energy is 64.1 nJ with a pulsewidth of 25.1 ns. After spectrally resolved measurements, the step-like pulse is proved to be induced by the dual wavelength oscillation. It is the first report of rectangular pulsed output in the mode-locked Raman fiber laser to the best of our knowledge.

Выбор параметров многофункционального трансформатора

The article considers power supply sources for electrotechnological installations involving induction heating, which include semiconductor converters for producing sine-wave and rectangular voltage pulses, in particular, symmetrical bridge and half-bridge circuits, as well as ferromagnetic frequency multipliers with an even frequency multiplication ratio. Methods for increasing the frequency by a factor of two and four by means of multifunctional transformers are investigated taking as an example their connection to converters with sine-wave and rectangular output signals. Graphic dependencies of the voltages across the winding terminals and fluxes in the multifunctional transformer core when being energized by signals with the above-mentioned waveforms are presented, which confirm that the output signal waveform across the load does not depend on the signal waveform applied to the multifunction transformer. The advantages of using a combination of cascade-connected semiconductor and ferromagnetic frequency multipliers are described. The working processes occurring in the system during its operation with different durations of the multifunctional transformer core saturation intervals are analyzed. A technique for parametrically synthesizing a ferromagnetic frequency converter using an approximate harmonic analysis (the Bessel method) is given. The article presents basic correlations for determining the converter electromagnetic parameters with the use of a hyperbolic sine approximation, namely, the amplitudes of the second and fourth induction harmonic components in the idle mode and for operation with a series and/or shunt capacitive compensation capacitor, and the induction component from the bias winding. The current through the compensating capacitor is calculated, and its capacitance is determined. Brief conclusions from the study results are formulated.

A 10-Way Power Divider Based on a Transducer and a Radial Junction Operating in the Circular TM01 Mode

This work presents a 10-way Ku-band power divider using a mode transducer and a radial junction connected by an overmoded circular waveguide operating in the TM 01 mode. The circular symmetry of this mode has been exploited to obtain a power divider with the rectangular output ports radially distributed along the broad wall of the waveguides in H-plane configuration. This topology provides the same amplitude and phase for all the output ports. At the same time, a compact profile has been obtained, introducing a simple manufacturing for the two components of the divider. The first component is a mode transducer converting the TE 10 mode in the rectangular waveguide to the TM 01 mode in the circular waveguide. It is based on a novel topology providing a very high purity in the mode conversion with an attenuation for the other propagating mode, the TE 11c , higher than 60 dB. The second component is a 10-way radial junction that must work under the excitation of the TM 01 , whose special features, since this mode is not the fundamental one of the circular waveguide, will be highlighted. The final design has been validated with an experimental prototype, proposing a manufacturing based on four simple parts. This has been the key to obtain an experimental prototype with specifications in the state-of-the-art. The measured efficiency is better than 96.5% in a 16.7% relative frequency bandwidth from 11 GHz to 13 GHz, with return losses better than 25 dB in the common port. The measured difference between the signals at the output ports of the prototype is ±0.3 dB for the amplitudes and ±0.45° for the phases. A comparison of the obtained results with another divider based on the TE 01 mode shows the potential of the presented design for becoming an alternative to the more extended TE 01 -based power dividers.

A terahertz spatial power combiner based on 2D periodic hole-shaped grating using nongradient optimization method

ABSTRACTThis paper describes a terahertz spatial power combiner based on a periodic hole-shaped hologram for a two-dimensional (2D) horn antenna array. The combiner consists of a 2D array of rectangular horns, a dielectric hole-shaped hologram, a focusing reflector, and a receiving horn antenna. The hologram is realized as 2D periodic holes, which transforms the beams of the antenna array into a pseudoplane wave. The transformed wave is coupled into a rectangular output horn antenna by a parabolic reflector with a shaped surface relief. The field distribution on the receiving plane can be obtained by using a nongradient optimization method to optimize the reflector surface. An example operating at 300 GHz is described. The theoretical power combining efficiency is about 63.1%. The computed field distribution agrees well with the result obtained using the commercial software FEKO Suite.

Octave bandwidth in‐line rectangular waveguide‐to‐coaxial transition using oversized mode conversion

A very low-loss in-line rectangular waveguide-to-coaxial transition covering an octave bandwidth is presented. In order to obtain such frequency coverage, the transition employs oversized mode conversion, i.e. the rectangular waveguide dimensions are internally enlarged to modify the cavity cutoff frequency while obtaining good matching properties for a standard rectangular waveguide output port. A four-step ridge transformer is included for the TE-to-TE10 mode conversion in the whole frequency range. The transition, completed with a commercial SMA connector for the coaxial port, exhibits a return loss of around 25 dB with 0.1 dB insertion loss when measured in back-to-back configuration in the 10–20 GHz frequency range. From these results, an input matching around 30 dB and an insertion loss around 0.05 dB for a stand-alone transition can be inferred.

Backward-Wave Oscillator Operating in Low Magnetic Fields Using a Hybrid-TE11 Mode

We present the design of a backward-wave oscillator based on a novel slow-wave structure (SWS) operating under low magnetic field conditions (<0.2 T). The design features a high-power electron beam interacting in dual synchronism with TM01 and hybrid TE11 modes. By exploiting mode control techniques, low magnetic fields with asymmetrical beam trajectories, a dominant interaction with the higher frequency hybrid TE11 mode is established. We present a design of the full interaction circuit, which also features a compact mode converter and an output coupler to produce a TE01 mode at the dual rectangular waveguide output. Simulations with a high-frequency structural simulator demonstrate dual-mode backward wave synchronism. A quantitative analysis of the electric field profiles is also presented. We also use a particle-in-cell (PIC) solver to predict the SWS performance under hot-test facility specific conditions. Using a 490-kV, 84-A electron beam under a guiding magnetic field of 0.15 T, PIC simulations predict an output power of 18 MW at 5 GHz with a peak power efficiency of 44%.

Octagonal CMOS Image Sensor for Endoscopic Applications

An octagonal shaped CMOS image sensor (CIS) has been developed for endoscopic applications. The octagonal shape of the outlined die is also applied to the pixel matrix which has suppressed corners, resulting in an octagonal pixel matrix of 422'640 effective pixels. The sensor die fits on a circumference of 3.2 mm diameter being this the best die cut ratio between the cut corners and the pixel placement. The missing pixels on the corners are internally compensated by the readout electronics to maintain a rectangular image output format of 680x680 pixels. This paper presents the solutions found to overcome the layout challenges of fitting both row and column logic on the same side of the diagonally cut corners. Furthermore, the sensor features an area efficient column parallel ADC converter, having on the column readout side, only 402 &#x3BC;m overhead total space between the utmost pixel row until the edge of the silicon die. This space is used to place CDS, ADC, column addressing, readout, additional electronics and power routing. The sensor also has a fully autonomous operation, requiring only an external clock supply to drive the internal state machine. The interface requires just 6 connections: 2 for power supply, 2 for bidirectional data and 2 for main clock supply. The frame rate and the exposure are configurable by register. The maximum frame rate is 50 frames per second (FPS) and data is delivered over LVDS serial data link. The integration time can be configured from 147 &#x3BC;s to 20.1 ms. The power supply is 3.3 V with internal Power-On-Reset (POR) and has a power consumption of 91 mW manufactured in 180 nm CIS process.

&lt;inline-formula&gt; &lt;tex-math notation="LaTeX"&gt;$S$ &lt;/tex-math&gt; &lt;/inline-formula&gt;-Band High-Efficiency Metamaterial Microwave Sources

In this paper, we present an S-band compact metamaterial microwave source, which is based on a rectangular output coupler and a new all-metal metamaterial slow-wave structure that has been proposed previously. Due to the reversed Cherenkov radiation of the metamaterial, this metamaterial microwave source can be considered as a new sort of backward wave oscillators (BWOs). The S-band metamaterial microwave source has been further studied and analyzed by using Ansoft HFSS and CST Particle studio particle-in-cell solver. The simulated results show that the electronic efficiency of this S-band metamaterial microwave source can go up to 90% with the peak output power of 4.5 MW. When compared with conventional BWOs, it has obvious advantages such as miniaturization and high electronic efficiency.

Experimental Investigation of Three-Dimensional Turbulent Jets Issuing from a Nozzle with a Rectangular Output Section

A detailed analysis of average dynamic characteristics of flow in a nozzle with a rectangular output section in relation to the nozzle aspect ratio parameter and Reynolds number has been carried out and its results have been generalized. It has been established that the flow velocity profile on the jet axis in the nozzle is determined by the parameter of its aspect ratio and by the jet initial velocity. A semiempirical formula that describes well the change in the maximum flow velocity in the main section of a three-dimensional jet is suggested.

Power efficiency of the active boundary layer control around the hump by a slotted synthetic jet generator

The present contribution summarizes the power efficiency of the active flow control of the boundary layer of air around a hump. The synthetic jet generator with a rectangular output part, i.e. a slot, is actuated using a modulated signal. The actuation of the synthetic jet is carried out by modulating the input voltage of acoustic transducers of the generator. This causes the decrease of the loss coefficient and the change of the mixing size area (e.g. wake). A comparison of three types of modulating signals and their influence on the loss coefficient is performed. The main advantages of modulated signal are then described.