A Short-Slot Waveguide Latching Ferrite Switch

A new type of latching switch, which consists of a short-slot waveguide junction loaded with a latched ferrite at the coupling section, is presented. The behavior of this switch is explained by application of the concept of a short-slot waveguide directional coupler. In order to estimate isolation characteristics, the phase constants of the two modes in the coupling section loaded with ferrite toroid are calculated. Practical construction based upon the calculated results has been carried out, and a switch with 8-percent bandwidth has been obtained.     

A 500 kW X-Band Air-Cooled Ferrite Latching Switch

The design of a high-power air-cooled microwave SPDT switch which is capable of operation at peak and average power levels of 500 kW and 666 watts, respectively, is described. The unit is of a differential phase shift circulator design employing 90/spl deg/ nonreciprocal phase shift elements which are forced air cooled. The phase shifter design employs dual ferrite toroids, "floating" in reduced height RG-51 waveguide. Two approaches are compared for heat sinking the phase shifter; namely the "H-beam" and the "I-beam" configurations. The results obtained indicate that the I-beam configuration is superior to the "H-beam" configuration. The switch exhibits an insertion loss of 0.6 dB maximum and isolation greater than 20 dB over a 100 MHz bandwidth centered at 9.375 GHz. The input VSWR of the switch over the frequency band is less than 1.28:1.     

A Temperature-Stable, Fail-Safe, Latching Ferrite TR Switch

Use of transmitting-receiving (TR) ferrite switches in place of gas-discharge devices improves the noise figure, life, and reliability of RADAR receivers. This paper describes a TR ferrite switch that employs 180/spl deg/ differential-phase-shift toroids to provide essentially constant isolation and insertion loss over a wide temperature range, independence of isolation with respect to RF power, and full receiver protection in case of driver failure. The ferrite switch is functionally a transfer device that is reciprocal in terms of transmission-coefficient amplitudes but nonreciprocal with respect to transmission phases. An experimental C-band 180/spl deg/ ferrite switch has provided isolation ranging from 38 to 45 dB and an insertion loss of 0.4 dB across a -40/spl deg/C to +75/spl deg/C range and a peak power-handling capacity of 130 kW measured at 0.001 duty. The switching energy, not including driver losses, is approximately 150 /spl mu/J. The preceding values of isolation and insertion loss compare with 36 and 0.8 to 1.1 dB, respectively, across the above temperature range, for the combination of fixed circulator, limiter, and one switchable circulator.     

35-GHz transferred electron amplifiers

GaAs transferred electron amplifiers with 110-mW saturated power output at 35 GHz have been designed and fabricated. Small signal gain of 13 dB, 3-GHz bandwidth, and noise figures as low as 16.2 dB have been observed. Two basic amplifier designs which have been investigated are described.     

High-efficiency 35-GHz GaAs MESFET's

Ka-band GaAs FET's with power output in excess of 200 mW and with efficiencies of more than 20 percent are described. Both ion-implanted and VPE-grown wafers were used. Deep UV (300-nm) lithography and chemical etching was employed to obtain a final gate length of 0.5 µm. These FET chips were flip-chip mounted and had a very low thermal resistance of 50°C/W for a total source periphery of 0.6 mm. At 35 GHz an output power of 220 mW with 21-percent efficiency at 3-dB gain was obtained from a 0.6-mm cell.     

A 50 to 94-GHz CMOS SPDT Switch Using Traveling-Wave Concept

A fully integrated single-pole-double-throw transmit/receive switch has been designed and fabricated in standard bulk 90-nm complementary metal-oxide semiconductor (CMOS) technology. Traveling wave concept was used to minimize the insertion loss at higher frequency and widen the operating bandwidth. The switch exhibits a measured insertion loss of 2.7 -dB, an input 1-dB compression point (input P_{1 dB}) of 15 dBm, and a 29-dB isolation at the center frequency of 77 GHz. The total chip size is only 0.57 times 0.42 mm ² including all testing pads. To our knowledge, this is the first CMOS switch demonstrated beyond 50 GHz, and the performances rival those monolithic microwave integrated circuit switches using standard GaAs PHEMTs     

A 5.2-GHz CMOS T/R Switch for Ultra-Low-Voltage Operations

A novel CMOS transmit/receive (T/R) switch suitable for ultra-low-voltage operations is presented in this paper. Due to the use of $LC$ resonators in the receiving and transmitting paths, enhanced performance in terms of insertion losses and isolation can be achieved. In addition, the forward-body-bias and body-floating techniques are also introduced to minimize the on-resistance of the MOSFETs at a reduced bias voltage. Using a standard 0.18-$mu{hbox {m}}$ CMOS process, a 5.2-GHz asymmetric T/R switch based on the proposed architecture is implemented. With a supply voltage of 0.6 V, the fabricated circuit exhibits 1.56-dB insertion loss, 17-dB isolation, and 11.2-dBm $P_{{rm in}-1 {rm{dB}}}$ in the receiving mode while the measured results in the transmitting mode are 2.02 dB, 31 dB, and 29.6 dBm, respectively.      

All-Optical Self-Routing Latching Switch Based on Active Mach–Zehnder Interferometer

A new architecture for an all-optical self-routing packet switch is reported. The control signals are optical pulses which can be easily extracted from the packet header. The experimental results at 40 Gb/s show a low power penalty and an on-off contrast ratio higher than 9 dB     

A Latching Ring-And-Post Ferrite Waveguide Circulator

This paper presents the performance and normalized design parameters for a latching ring-and-post ferrite circulator in waveguide. A C-band circulator has provided an insertion loss of 0.35 dB and a 20-dB isolation bandwidth of 17 percent. When the circulator was matched for higher maximum isolation (50 dB) but narrower bandwidth (10 percent) at room temperature, the 20-dB isolation bandwidth was 7.8 percent across the -40/spl deg/ to +75/spl deg/C temperature range. Low-loss operation was obtained at pulsed powers up to 7.5 kilowatts, and at least 20 dB of isolation was maintained up to 100 kilowatts. This performance, in conjunction with a switching speed of a fraction of a microsecond, permits the use of these circulators for transmitting-receiving functions in high-reliability RADARs.     

Normally On/Off Integrated Latching Acceleration Switch With Controlled Fracture Beams and Independent Multicontact

This letter reports an acceleration latching switch with integrated normally on/off paths. The normally on path, formed by notched beams connected in series, will be broken and latched to reach the open state when the acceleration exceeds the threshold. A multicontact is adopted for the normally off path, while both paths are mechanically separated from the proof mass to prevent them from the impact of the proof mass at the latched state. Experimental results show that the latching shock is 10 000 G, and the response time is about 0.1 ms. The normally on path has an on-state resistance of 4.0 $Omega$ and an allowable current of 200 mA, whereas the normally off path has an on-state resistance of 3.8 $Omega$ and a maximum current of 140 mA.      

A 35-GHz Isolator Using a Coaxial Solid-State Plasma in a Longitudinal Magnetic Field

The device considered in this study is a semiconductor isolator consisting of a circular waveguide with a cylindrical rod of n-type InSb mounted coaxially in the guide. To achieve nonreciprocal operation, the InSb was cooled to liquid nitrogen temperature, a dc magnetic field was applied parallel to the direction of propagation, and a circularly polarized signal was used to excite the waveguide containing the rod. The pertinent solution of Maxwell's equations was programmed for a digital computer to allow numerical evaluation of the characteristics of the isolator using an InSb rod in which losses were present. Experimental data for various parameters and the corresponding calculated data are presented and compared. Low forward loss is achieved with the present coaxial geometry because of strong power concentration effects within or outside of the InSb rod as a function of the direction of propagation. Two series of calculated mode patterns are presented that demonstrate two types of operation of the isolator in achieving a high loss for one direction of propagation, one depending on field displacement, the other on mode coupling. These data are again compared to the experimental evidence.     

A Miniaturized C-Band Digital Latching Phase Shifter

This paper describes a digital-latching phase shifter which combines the electrical advantages of waveguide design with the compactness of a strip transmission-line structure. Two multibit, nonreciprocal, C-band models are described, which combine the electronic drivers and the microwave structure in an 0.8 by 0.8 inch cross section designed specifically for half-wavelength stacking in an antenna array. A new technique of antisymmetric dielectric loading to convert microwave energy from a TEM mode in stripline transmission to a TE-type mode propagating in a dielectrically loaded rectangular waveguide is presented. Data for a one-bit model are presented along with an investigation into an optimum material choice. Temperature stability and peak power capability are also discussed. The performance of two multibit models are presented, including VSWR, insertion loss, and average power characteristics of the final microwave structures. Temperature variation of phase shift and peak power performance of these devices are also presented. Particular attention is given the electronic drivers for the multibit models which must latch the toroids into their remanent states. The driver circuit is designed to permit switching of each bit between states with a single wire trigger. Finally, the advantages of this design over previous miniaturized models are summarized, and further investigations into other features for greater optimization are suggested.     

35-GHz performance of single and quadruple power heterojunction HEMT's

The potential of single hetrojunction (SHJ) and quadruple heterojunction (QHJ) HEMT devices to provide power amplification at theKa-band frequencies has been measured. The power level observed, from QHJ devices that have gate lengths of 0.5 µm and gate widths of 200 µm, has been over +20 dBm when gain is compressed below the small signal level by 2 dB. The small-signal gain was 5.2 dB at 35 GHz. The power level demonstrated by the SHJ devices is lower than that of the QHJ devices due to the lower "two-dimensional electron gas" sheet carrier density. Our measurements have shown a saturated power level of +15.3 dBm devices of the same geometry as the above-mentioned QHJ devices. The power performance in both cases (QHJ and SHJ) has been obtained with high efficiencies of 38 and 21 percent, respectively. These performance data represent the highest levels of gain and power reported atKa-band frequencies from transistors that employ a 0.5-µm geometry.     

A Dual-Mode Latching Reciprocal Ferrite Phase Shifter

A ferrite phase shifter has been developed to provide latching reciprocal phase shift over a moderate frequency band. The principle of operation is based on the use of dual-mode circularly polarized waves in the active ferrite with nonreciprocal polarizers to select modes that provide reciprocal transmission phase. The physical structure of the phase shifter consists of a metallized assembly of ferrite and ceramic dielectric. A ferrite yoke is fitted over a portion of this assembly to permit latching operation. The completed phase shifter has a very simple geometry that can be produced at low cost and has relatively low insertion loss. The maximum cross-sectional dimensions are small and are consequently compatible with application in two-dimensional electronically scanned arrays. Experimental results are presented for an X-band design having a 10-percent bandwidth centered near 9 GHz.     

35-GHz static and 48-GHz dynamic frequency divider ICs using0.2-μm AlGaAs/GaAs-HEMTs

Two static and two dynamic frequency dividers based on enhancement and depletion 0.2-μm gate length AlGaAs/GaAs-high electron mobility transistor (HEMT) (f_T=60 and 55 GHz) technology were designed and fabricated. High-speed operations up to 35 GHz for the static frequency dividers and 48 GHz for the dynamic dividers, respectively, have been achieved. The single-ended input and differential outputs to ground simplify many applications. The power consumption is 250 mW for the divide-by-two dividers and 350 mW for the divide-by-four dividers using two supply voltages of 4 and -2.5 V     

Particle Simulation of a 35-GHz Third-Harmonic Low-Voltage Complex Cavity Gyrotron

A self-consistent particle simulation code has been developed for the research of a 35-GHz third-harmonic Low-voltage complex cavity gyrotron. Aided with microcomputer we use FORTRAN to simulate the process of interaction between electron beam and electromagnetic field. About 7000 macro particles are included at the same time. In the program many useful physical graphs are accessible for the further research of this kind of gyrotron such as the field profile, electrons distribution in various spaces, output power, efficiency and et al. Such simulation results may be helpful to the optimization of devices operation parameters     

一种适用于锁式铁氧体器件的驱动电路

分析了锁式铁氧体器件的等效负载特性,在此基础上给出了专用驱动电路的设计,并分析了其原理以及应用结果。从中可以看出,该电路能用于驱动所有锁式铁氧体器件,特别适用于驱动锁式铁氧体移相器。     

Design and analysis of a coaxial coupler for a 35-GHz gyroklystronamplifier

A single rectangular TE₁₀ feed four-slot coaxial coupler is designed and built for excitation of a TE₀₁₁ cylindrical cavity mode for use in high-power millimeter-wavelength gyroklystron amplifiers. A high degree of mode purity is obtained and matching of the cavity to the input line is studied. A model based on the mode-matching technique and dipole radiators has been formulated to predict operation of this coupler. The resulting numerical code is capable of finding resonant frequency and cavity bandwidth in a small fraction of the time taken by more general finite-difference/finite-element design tools. The model can be extended to self-consistently include an electron beam, and the model is compared to a coupler design based on Hewlett-Packard's High-Frequency Structure Simulator code. The coupler has been successfully used in a high-power gyroklystron-amplifier experiment     

A New Type of Latching Switchable Ferrite Junction Circulator

This paper presents an approximate theory and initial performance data for a new type of latching, switchable, ferrite junction circulator that is well suited for applications requiring fast (fractions of or several microseconds), low-energy (tens of microjoules in the microwave region) switching. The novelty of the device is the use of oppositely magnetized ferrite cylinder-and-ring assemblies within the region of circulation. The approximate theory yields the radius for circulation, bandwidth, and input impedance as functions of material properties and frequency. Operation of latched circulators has been demonstrated on assemblies operating in the region of 7.3 and 5.4 GHz. Insertion losses from 0.25 to 0.4 dB, 20-dB isolation bandwidths from 2.4 to 8.3 percent, and switching energies from 15 to 30 /spl mu/J have been obtained.     

Wideband Phase-Compensated VGA with PMOS Switch in 40-nm CMOS for 120-GHz Band

Journal of Infrared, Millimeter, and Terahertz Waves - This paper presents a 120-GHz wideband phase-compensated variable gain amplifier (VGA) with a p-type metal–oxide–semiconductor...