DOCSLIB.ORG

Oscillator Design Techniques Allow High Frequency Application Of

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Oscillator Design Techniques Allow High Frequency Application Of OSCILLATOR DESIGN TECHNIQUES ALLOW HIGH FREQUENCY APPLICATIONS OF INVERTED MESA RESONATORS By Kurt Wessendorf lithium niobate. The arrays are comprised of Sandia National Laboratories electrodes that alternate polarities. When an RF signal voltage of the proper frequency is Albuquerque, New Mexico applied across them, the surface of the crystal expands and contracts, generating a Tom Payne displacement wave on the surface of the President crystal. Avance Technology TmT Bulk Acoustic Wave Resonator Cedar City, Utah Model By using inverted-mesa techniques to Bulk acoustic wave (BAW) resonators selectively thin the resonator, the practical operate on entirely different principles. The upper frequency range of bulk wave crystal displacement wave produces a resonating oscillators has risen dramatically over the past vibration which travels through the crystal. The several years. A new technology called Tab- crystallographic orientation used in mesa Technology (TmT) has paved the way for manufacturing BAW devices is crucial to their new design approaches in telecommunications performance characteristics. For applications applications including small, portable high- in the Megahertz range, the AT-cut is the most frequency equipment such as pagers, cellular common orientation because of its relatively telephones, keyless entry and other wireless low temperature coefficients. Figure 1 is the communications systems. Many designers electrical equivalent model of the AT-Cut have shied away from these new devices resonator. This model shows only the because of the lack of standardized design fundamental and the first two overtones of the practices. Fortunately, as this article will resonator. Also, not shown in this model, are demonstrate, many classic bulk wave designs the spurious modes that can exist. These can be adapted to high frequency operation modes are process driven and can be kept when the new crystals are used in the relatively lossy in a well designed and fundamental mode. fabricated resonator. C0 is the static capacitance of the resonator which is in Most existing high-frequency equipment is parallel with the motional arms (Cm, Lm and Rm) built around surface acoustic wave (SAW) which are a function of the piezoelectric resonators. The SAW resonator consists of properties of the quartz. two transducers with arrays of fine metal electrodes deposited on a highly polished piezoelectric substrate such as quartz or Using inverted mesa technology, crystals can now be produced in the fundamental frequency range of 40 MHz to 200 MHz with overtones to 600 MHz. The inverted mesa process uses chemical etching to reduce the thickness of the quartz in the center region of the blank, leaving a thicker outer ring for added crystal strength. Inverted mesa technology permits higher frequencies than were previously possible with flat AT quartz crystals. The tiny geometry of these resonators also minimizes the static capacitance (C0) of the devices which allows for higher loaded Qs at Fiigure 1. AT-Cut Resonator Modell high frequencies. However, the use of inverted mesa crystals has been limited by their high Figure 2 graphically illustrates the cost and the difficulties associated with volume resonator’s reactive impedance, X , versus e production. frequency [1]. (This graph is not drawn to scale). TmT involves batch processing crystals using photolithographic techniques similar to those used in semiconductor processing. In a process developed by Avance Technology, a SaRonix company located in Cedar City, Utah, one by two inch quartz wafers are lapped and polished to approximately 3 mil thickness. 130 individual resonators approximately 50 by 170 mil in size are formed photolithographically on each wafer with the resonating region etched down to 0.5 mil or less depending on the desired frequency. Calibration to the exact frequency is accomplished by evaporating a thin gold layer onto the resonating region. The individual resonators are attached at their Fiigure 2. Resonator Reactiive Impedance vs. Frequency supporting 3 mil end onto headers using conductive epoxy and then hermetically sealed Typically an oscillator will be using the into a cylindrical metal or rectangular ceramic resonator in the inductive region, or as a enclosure. resistive element very near fs. The fundamental resonant frequency of the AT-cut crystals This manufacturing technology makes generally specified today is 1-30 MHz. In AT- volume production of consistent quality, high cut crystals, the thickness of the crystal wafer frequency crystals possible. The thin determines the frequency–the thinner the wafer resonating region of TmT crystals is the higher the frequency. Unfortunately, thin cantilevered from a thicker base, enabling a wafers are very fragile and difficult to handle much smaller crystal design. The inherent without breakage, limiting the fundamental small size of these unique crystals makes it frequency of these devices. The AT-cut possible to package the miniature devices in 2 resonator can also be operated on odd mm by 5 mm tubular casings similar to those mechanical overtones of the fundamental used in the watch crystal industry. When frequency, generally the third and fifth. These mounted in a conventional hybrid oscillator overtones are higher Q than the fundamental circuit, the TmT crystal is hermetically sealed in and demonstrate superior aging its own enclosure. This eliminates the most characteristics. common sources of crystal failure in hybrid SaRoniix/Sandiia Natiionall Laboratoriies/Page 2 oscillators–blank fractures and contamination. design depends on a wide range of variables, The low mass of quartz blanks mounted in typically a one-port BAW oscillator can be small, sealed metal or ceramic packages many times more efficient and run at lower results in rugged components that are much overall currents than a 2-port SAW based less susceptible to shock, vibration and design. The circuits presented here can handling damage. These devices provide an produce 0 dBm outputs with currents from 3 attractive alternative to SAW devices in many mA to 5 mA and useful outputs (-10 dBm) with applications. as little as 0.6 mA of dc current. High-power (15 dBm) low current (11 mA) designs which High-Frequency Oscillator Designs are demonstrating >60% power efficiency at frequencies to 200 MHz using these new resonators are in development*. Another Traditional 2-port SAW oscillator designs distinct difference between SAW devices and are based upon a 50W gain block, Figure 3. BAW (AT-cut) devices is the frequency versus The power efficiency and minimum operating temperature response. Figure 4 and Figure 5 power of this type of design is limited by the are the temperature response curves gain block (amplifier) and the low impedance respectively for the SAW and BAW devices. splitter. Since the gain blocks typically use shunt feedback for matching, relatively large bias currents (tens of milliamps) are required to achieve the gain required to drive the low impedance SAW and splitter. In many designs milliamp or sub-milliamp currents may be desired to meet a low overall current (thus power) budget of a system. Fiigure 4. Frequency vs. Temperature of SAW Deviice [2] Fiigure 3. Two-Port SAW Osciillllator Ciircuiit One-port (negative resistance) oscillators can offer greater design flexibility than 2-port designs. The chief advantage is that the circuit can be designed to optimize the current used in the oscillator transistor for the oscillator configuration chosen. Also one can more optimally match a transistor to the load via low- bandwidth, reactive networks than via resistive shunt feedback. In a one-port design, the oscillator itself may be part of the matching structure which also simplifies the design. Fiigure 5. Frequency vs. Temperature Curves for AT-Cut Although overall efficiency (h) of any oscillator Resonator [3] SaRoniix/Sandiia Natiionall Laboratoriies/Page 3 Fiigure 6. Fundamentall Mode Piierce Osciillllator The AT-cut resonator temperature response is approximately three times less The Pierce oscillator with fundamental than the typical SAW temperature response. mode resonator (Y1) is shown in Figure 6. This By careful selection of crystal angle one can circuit is probably the most popular oscillator obtain an AT resonator with temperature design type and operates with the resonator as variations of less than ±10 ppm over a an inductive element. It provides a relatively temperature range of -40° C to 75°. Finally, low distortion sine wave to RL if the oscillator is SAW devices can't be economically produced properly designed. The bias circuit is relatively at low volumes because of the tooling cost to stable and is easy to implement. RC is chosen produce mask sets. for the desired dc bias current and if Rf is chosen to be ~50 times RC then the transistor The ability to achieve fundamental will be biased with the collector voltage (dc) at frequencies up to 200 MHz with AT-cut BAW approximately ½ of +V. The ratio of oscillation crystals can mean dramatic reduction in power amplitude (collector to base) is approximately consumption in many applications. Volume C1/C2. C1 is usually chosen to dominate the production costs typically compare to SAW transistor input impedance and therefore will devices, while sampling is far more be relatively large. The magnitude of XC1 economical. should be in the 50 W to 200 W range. Making C2 two to five times smaller than C1 to creates Today good quality high-frequency a large amplitude of oscillation (at the collector) transistors and passive components are readily and a good impedance match to RL. At the available in low-cost, surface-mount packages. frequency of oscillation |XC1|+|XC2|= |Xe| where When these devices are used in conjunction Xe is the inductive reactance of the resonator with high frequency TmT resonators, many Y1, and XC1 and XC2 are the capacitive classic bulk-wave oscillator designs are reactances of C1 and C2 respectively. The realizable at high frequencies. These designs resonator is designed to be resonant with CL can be easily implemented with fundamental- C1C2 mode resonator operation with no inductors in which is at the desired frequency [4].
Load more

Recommended publications
  • Pll Applications
    PLL APPLICATIONS Contents 1 Introduction 1 2 Tracking Band-Pass Filter for Angle Modulated Signals 2 3 CW Carrier Recovery 2 4 PLL Frequency Divider and Multiplier 3 5 PLL Amplifier for Angle Modulated Signals 3 6 Frequency Synthesis and Angle Modulation by PLL 4 7 Coherent Demodulation by APLL 5 7.1 PM Demodulator . 5 7.2 FM Demodulator . 5 7.3 AM Demodulator . 6 8 Suppressed Carrier Recovery Circuits 6 8.1 Squaring Loop . 6 8.2 Costas Loop . 7 8.3 Inverse Modulator . 8 9 Clock Recovery Circuit 9 1 Introduction The PLL is one of the most commonly used circuits in electrical engineering. This section discusses the most important PLL applications and gives guidelines for the design of these circuits. A detailed discussion of different applications is beyond the scope of this article; for a comprehensive survey see [1] and [2]. The baseband model of analog phase-locked loop and its linear theory were discussed on the lecture. In all PLL applications, the phase-locked condition must be achieved and maintained. In order to avoid distortion, many applications require operation in the linear region, that is, the total variance of the phase error process resulting from noise and modulation must be kept small enough. If the PLL operates in the linear region then the linearized baseband model may be used in circuit design and development. Recall that only the PD output, VCO control voltage, input phase θi(t) and output phase θo(t) appear in the PLL baseband model. All these signals are low-frequency signals.
    [Show full text]
  • PLL) for Wideband Clock Generation
    UNIVERSITY OF CALIFORNIA Los Angeles A Multi-loop Calibration-free Phase-locked Loop (PLL) for Wideband Clock Generation A dissertation submitted in partial satisfaction of the requirements for the degree Doctor of Philosophy in Electrical Engineering by Dihang Yang 2019 c Copyright by Dihang Yang 2019 ABSTRACT OF THE DISSERTATION A Multi-loop Calibration-free Phase-locked Loop (PLL) for Wideband Clock Generation by Dihang Yang Doctor of Philosophy in Electrical Engineering University of California, Los Angeles, 2019 Professor Asad. A. Abidi, Chair In a wide-band RF system, the RF channel is located within 50 MHz to 9 GHz. A high- frequency resolution phase-locked loop (PLL) with 100% tuning range oscillator is the core to generate the RF carrier frequency which covers such a wide range. The phase noise and spurs of the PLL are required to be low to avoid degrading RF system performance. A PLL applies Σ∆ modulation to increases its resolution and is known as a fractional-N PLL, but Σ∆ modulation introduces considerable quantization noise into the loop. The nonlinearity of the PLL also converts part of the noise into fractional-N spurs. Noise cancellation is usually applied to eliminate this quantization noise. Calibration, often with long settling time, is necessary to maintain cancellation efficiency. Power intensive calibration is also required to notch spurious tones. In this thesis, we first investigate the delay-locked loop (DLL) and attempt to use DLL to replace PLL as an RF frequency synthesizer. An LTI model of DLL is established, which indicates the limitation of DLL as a high-performance synthesizer.
    [Show full text]
  • 10/29/07 11:40 PM Frequency Doublers
    10/29/07 11:40 PM Frequency Doublers FREQUENCY DOUBLERS AN UNDERSTANDING AIDS IN EFFICIENT TUBE OPERATION National Radio Institute No. 19C A very high-powered oscillator/transmitter will not maintain its frequency at reasonably constant value. For this reason, high-power oscillators are seldom used. Instead, a master oscillator is designed to have the best possible frequency stability, and then a series of amplifying stages is used to get the required power. With this arrangement, it is possible to draw very little power from the oscillator, thus insuring its frequency stability. Frequency Multiplication. It may happen that crystals cannot produce a frequency as high as the required output frequency. If so, it is possible to design an intermediate amplifier so that it has a strong harmonic output. The second or third harmonic of the crystal frequency may then be taken from this amplifier and amplified by the succeeding intermediate amplifier stages. This lets us get an output frequency that may be two or three times the master oscillator frequency. By using a chain of multipliers in this manner, we can get frequencies of four, six, or any other multiple of the master oscillator output. The most practical form of oscillator possessing a high degree of frequency stability is one in which the frequency is determined by mechanical oscillation of a piezoelectric quartz crystal. Because of such desirable characteristics, almost all modern transmitters use some form of crystal-controlled master oscillator. The natural mechanical resonance of a crystal is determined primarily by its thickness, and crystals are ground very carefully to a definite thickness to make them oscillate at some specific frequency.
    [Show full text]
  • Fully-Integrated, Fixed Frequency, Low-Jitter Crystal Oscillator Clock
    CDC421AXXX www.ti.com ....................................................................................................................................................................................................... SCAS875–MAY 2009 Fully-Integrated, Fixed-Frequency, Low-Jitter Crystal Oscillator Clock Generator 1FEATURES APPLICATIONS • 2• Single 3.3-V Supply Low-Cost, Low-Jitter Frequency Multiplier • High-Performance Clock Generator, Incorporating Crystal Oscillator Circuitry with DESCRIPTION Integrated Frequency Synthesizer The CDC421Axxx is a high-performance, • Low Output Jitter: As low as 380 fs (RMS low-phase-noise clock generator. It has an integrated integrated between 10 kHz to 20 MHz) low-noise, LC-based voltage-controlled oscillator • (VCO) that operates within the 1.75 GHz to 2.35 GHz Low Phase Noise at 312.5 MHz: frequency range. It has an integrated crystal oscillator – Less than –120 dBc/Hz at 10 kHz and that operates in conjunction with an external AT-cut –147 dBc/Hz at 10-MHz offset from carrier crystal to produce a stable frequency reference for a • Supports Crystal or LVCMOS Input phase-locked loop (PLL)-based frequency Frequencies at 31.25 MHz, 33.33 MHz, and synthesizer. The output frequency (fOUT) is 35.42 MHz proportional to the frequency of the input crystal (fXTAL). • Output Frequencies: 100 MHz, 106.25 MHz, 125 MHz, 156.25 MHz, 212.5 MHz, 250 MHz, and The device operates in 3.3-V supply environment and 312.5 MHz is characterized for operation from –40°C to +85°C. The CDC421Axxx is available in a QFN-24 4-mm × • Differential Low-Voltage Positive Emitter 4-mm package. Coupled Logic (LVPECL) Outputs • The CDC421Axxx differs from the CDC421xxx in Fully-Integrated Voltage-Controlled Oscillator the following ways: (VCO): Runs from 1.75 GHz to 2.35 GHz • Device Startup • Typical Power Consumption: 300 mW The CDC421Axxx has an improved startup circuit • Chip Enable Control Pin to enable correct operation for all power-supply • Available in 4-mm × 4-mm QFN-24 Package ramp times.
    [Show full text]
  • Graphene Frequency Multipliers
    Graphene Frequency Multipliers The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation Han Wang et al. “Graphene Frequency Multipliers.” Electron Device Letters, IEEE 30.5 (2009): 547-549. © 2009 Institute of Electrical and Electronics Engineers. As Published http://dx.doi.org/10.1109/LED.2009.2016443 Publisher Institute of Electrical and Electronics Engineers Version Final published version Citable link http://hdl.handle.net/1721.1/54736 Terms of Use Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. IEEE ELECTRON DEVICE LETTERS, VOL. 30, NO. 5, MAY 2009 547 Graphene Frequency Multipliers Han Wang, Daniel Nezich, Jing Kong, and Tomas Palacios, Member, IEEE Abstract—In this letter, the ambipolar transport properties of graphene flakes have been used to fabricate full-wave signal rectifiers and frequency-doubling devices. By correctly biasing an ambipolar graphene field-effect transistor in common-source configuration, a sinusoidal voltage applied to the transistor gate is rectified at the drain electrode. Using this concept, frequency multiplication of a 10-kHz input signal has been experimentally demonstrated. The spectral purity of the 20-kHz output signal is excellent, with more than 90% of the radio-frequency power in the 20-kHz frequency. This high efficiency, combined with the high electron mobility of graphene, makes graphene-based frequency multipliers a very promising option for signal generation at ultra- high frequencies. Index Terms—Frequency doublers, frequency multipliers, full- wave rectifiers, graphene field-effect transistors (G-FETs).
    [Show full text]
  • High-Harmonic Mm-Wave Frequency Multiplication Using a Gyrocon-Like
    Proceedings of IPAC2016, Busan, Korea MOPMY036 HIGH-HARMONIC MM–WAVE FREQUENCY MULTIPLICATION USING A GYROCON–LIKE DEVICE∗ F. Toufexisy1, S.G. Tantawi, A. Jensen, V.A. Dolgashev, A. Vrielink1, M.V. Fazio, SLAC, Menlo Park, CA 94025 P. Borchard, Dymenso LLC, San Francisco, CA 94115 1Also at Department of Electrical Engineering, Stanford University, Stanford, CA 94305 Abstract 1 Traditional linear interaction RF sources, such as Klystrons and Traveling Wave Tubes, fail to produce sig- nificant power levels at millimeter wavelengths. This is because their critical dimensions are small compared to the wavelength, and the output power scales as the square of the 0 Hybrid Coupler wavelength. We present a vacuum tube technology, where Dummy Features for 2 cm the device size is inherently larger than the operating wave- Field Symmetry length. We designed a low–voltage mm–wave source, with Figure 1: Vacuum model and surface electric fields of the an output interaction circuit based on a spherical sector cav- output circuit. ity. This device was configured as a phased-locked frequency multiplier. We report the design and cold test results of a proof-of-principle fifth harmonic frequency multiplier with 84keV an output frequency of 57.12 GHz. INTRODUCTION Millimeter–waves refer to the part of the frequency spec- 49keV trum above 50 GHz up to 1 THz. This part of the spectrum is still unexploited because of the lack of compact mm-wave sources [1–4] – especially amplifiers – that are able to pro- vide substantial amount of power. Compact high power mm-wave sources will enable several applications such as spectroscopy, high–resolution medical imaging, navigation through sandstorms, spectroscopic detection of explosives, Figure 2: CST Particle Tracking.
    [Show full text]
  • An All-Solid-State Broad-Band Frequency Multiplier Chain at 1500 Ghz Goutam Chattopadhyay, Senior Member, IEEE, Erich Schlecht, Member, IEEE, John S
    1538 IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 52, NO. 5, MAY 2004 An All-Solid-State Broad-Band Frequency Multiplier Chain at 1500 GHz Goutam Chattopadhyay, Senior Member, IEEE, Erich Schlecht, Member, IEEE, John S. Ward, John J. Gill, Hamid H. S. Javadi, Frank Maiwald, Member, IEEE, and Imran Mehdi, Member, IEEE Abstract—We report the results of a high-performance all-solid- provide a high-power frequency-agile source beyond 100 GHz. state broad-band frequency multiplier chain at 1500 GHz, which Breakthroughs in device fabrication techniques, specifically uses four cascaded planar Schottky-barrier varactor doublers. The the usage of gallium–arsenide (GaAs)-based substrateless multipliers are driven by monolithic-microwave integrated-circuit- based high electron-mobility transistor power amplifiers around and membrane technologies [11] along with metal beamleads 95 GHz with 100–150 mW of pump power. The design incorporates for coupling probes and RF/dc ground contacts have made balanced doublers utilizing novel substrateless and membrane de- low-loss planar Schottky varactor diode design at terahertz vice fabrication technologies, achieving low-loss broad-band multi- frequencies feasible. Improvement of electromagnetic and pliers working in the terahertz range. For a drive power of approx- nonlinear computational tools such as Ansoft’s High Frequency imately 100 mW in the 88–99-GHz range, the doublers achieved 1 room-temperature peak efficiencies of approximately 30% at the Structure Simulator (HFSS) and Agilent Technologies’ Ad- 190-GHz stage, 20% at 375 GHz, 9% at 750 GHz, and 4% at the vanced Design System (ADS)2 , and advanced device modeling 1500-GHz stage.
    [Show full text]
  • Variable Capacitors in RF Circuits
    Source: Secrets of RF Circuit Design 1 CHAPTER Introduction to RF electronics Radio-frequency (RF) electronics differ from other electronics because the higher frequencies make some circuit operation a little hard to understand. Stray capacitance and stray inductance afflict these circuits. Stray capacitance is the capacitance that exists between conductors of the circuit, between conductors or components and ground, or between components. Stray inductance is the normal in- ductance of the conductors that connect components, as well as internal component inductances. These stray parameters are not usually important at dc and low ac frequencies, but as the frequency increases, they become a much larger proportion of the total. In some older very high frequency (VHF) TV tuners and VHF communi- cations receiver front ends, the stray capacitances were sufficiently large to tune the circuits, so no actual discrete tuning capacitors were needed. Also, skin effect exists at RF. The term skin effect refers to the fact that ac flows only on the outside portion of the conductor, while dc flows through the entire con- ductor. As frequency increases, skin effect produces a smaller zone of conduction and a correspondingly higher value of ac resistance compared with dc resistance. Another problem with RF circuits is that the signals find it easier to radiate both from the circuit and within the circuit. Thus, coupling effects between elements of the circuit, between the circuit and its environment, and from the environment to the circuit become a lot more critical at RF. Interference and other strange effects are found at RF that are missing in dc circuits and are negligible in most low- frequency ac circuits.
    [Show full text]
  • EURO QUARTZ TECHNICAL NOTES Crystal Theory Page 1 of 8
    EURO QUARTZ TECHNICAL NOTES Crystal Theory Page 1 of 8 Introduction The Crystal Equivalent Circuit If you are an engineer mainly working with digital devices these notes In the crystal equivalent circuit above, L1, C1 and R1 are the crystal should reacquaint you with a little analogue theory. The treatment is motional parameters and C0 is the capacitance between the crystal non-mathematical, concentrating on practical aspects of circuit design. electrodes, together with capacitances due to its mounting and lead- out arrangement. The current flowing into a load at B as a result of a Various oscillator designs are illustrated that with a little constant-voltage source of variable frequency applied at A is plotted experimentation may be easily modified to suit your requirements. If below. you prefer a more ‘in-depth’ treatment of the subject, the appendix contains formulae and a list of further reading. At low frequencies, the impedance of the motional arm of the crystal is extremely high and current rises with increasing frequency due solely to Series or Parallel? the decreasing reactance of C0. A frequency fr is reached where L1 is resonant with C1, and at which the current rises dramatically, being It can often be confusing as to whether a particular circuit arrangement limited only by RL and crystal motional resistance R1 in series. At only requires a parallel or series resonant crystal. To help clarify this point, it slightly higher frequencies the motional arm exhibits an increasing net is useful to consider both the crystal equivalent circuit and the method inductive reactance, which resonates with C0 at fa, causing the current by which crystal manufacturers calibrate crystal products.
    [Show full text]
  • The Radio-Frequency System Guide for the Accelerator Test Facility Prepared By: Michael Zarcone Reviewed By: ES&H Approved By: Department Chair Committee
    Number: 1.0.2 Revision: 1 BROOKHAVEN NATIONAL LABORATORY PHYSICS DEPARTMENT Effective: 04/01/2004 Page 1 of 5 Subject: The Radio-Frequency System Guide for the Accelerator Test Facility Prepared by: Michael Zarcone Reviewed by: ES&H Approved by: Department Chair Committee THE RADIO-FREQUENCY SYSTEM GUIDE FOR THE ACCELERATOR TEST FACILITY 1. The Radio-Frequency System 1.1 Introduction The accelerator RF system operates at 2856 MHz. The internal dimensions of the accelerator cavities, klystron, and waveguide components determine the frequency. Frequency adjustment of about 0.1 MHz is possible by changing the temperature of the components by adjusting the water-cooling set point. The normal water temperature is at 44.60 ± 0.05C. The choice of operating frequency was due to the 50-year legacy of development and manufacturing at this frequency and availability of standard components developed at Stanford University and SLAC. Pulsed power is available at up to 6 pulses per second with pulse widths from 2.5 to 10µs. Total peak power of 20 to 70 megawatts is available depending on the klystron(s) used. The power is distributed as follows: Electron gun 4-10 megawatts Accelerating sections 5-30 megawatts (each) The pulses of RF power are rectangular with rise and fall times of about 400 nanoseconds. Pulse amplitude should be constant to ±0.3% with a pulse-to-pulse repeatability of better than ±0.05%. Noise and FM jitter should not exceed 0.5 degree during the pulse. The source of RF is a temperature controlled crystal oscillator at 40.8 MHz.
    [Show full text]
  • Microwave Frequency Multiplier
    IPN Progress Report 42-208 • February 15, 2017 Microwave Frequency Multiplier Jose E. Velazco* ABSTRACT. — High-power microwave radiation is used in the Deep Space Network (DSN) and Goldstone Solar System Radar (GSSR) for uplink communications with spacecraft and for monitoring asteroids and space debris, respectively. Intense X-band (7.1–8.6 GHz) micro- wave signals are produced for these applications via klystron and traveling-wave microwave vacuum tubes. In order to achieve higher data rate communications with spacecraft, the DSN is planning to gradually furnish several of its deep space stations with uplink systems that employ Ka-band (34-GHz) radiation. Also, the next generation of planetary radar, such as Ka-Band Objects Observation and Monitoring (KaBOOM), is considering frequencies in the Ka-band range (34–36 GHz) in order to achieve higher target resolution. Current com- mercial Ka-band sources are limited to power levels that range from hundreds of watts up to a kilowatt and, at the high-power end, tend to suffer from poor reliability. In either case, there is a clear need for stable Ka-band sources that can produce kilowatts of power with high reliability. In this article, we present a new concept for high-power, high-frequency generation (including Ka-band) that we refer to as the microwave frequency multiplier (MFM). The MFM is a two-cavity vacuum tube concept where low-frequency (2–8 GHz) power is fed into the input cavity to modulate and accelerate an electron beam. In the sec- ond cavity, the modulated electron beam excites and amplifies high-power microwaves at a frequency that is a multiple integer of the input cavity’s frequency.
    [Show full text]
  • Performance Limitations of Varactor Multipliers
    Page 312 Fourth International Symposium on Space Terahertz Technology Performance Limitations of Varactor Multipliers. Jack East Center for Space Terahertz Technology, The University of Michigan Erik Kollberg Chalmers University of Technology Margaret Frerking NASA/JPL ABSTRACT Large signal nonlinear device circuit modeling tools are used to design varactor harmonic multipliers for use as millimeter and submillimeter wave local oscillator pump sources. The results predicted by these models are in reasonable agreement with experimental results at lower frequencies, but the agreement becomes worse as the power level or frequency increases. We will discuss an improved varactor device model and compare results from the new model with both conventional models and experimental data. I. Introduction The Schottky barrier varactor frequency multiplier is a critical component of mil- limeter wave and submillimeter wave receiver systems. A variety of modeling tools are available to help in the design of the multipliers. The modeling is a combination of linear and nonlinear analysis to find the current and voltage waveforms across the varactor placed in the multiplier circuit. The conventional approach uses the harmonic balance1 '2 or multiple reflection technique'. These techniques start with a time domain approximation for the voltage across the device and time domain information for the nonlinear device and frequency domain information from the linear circuit to find the final waveforms across the device. These techniques are available in many commercial circuit simulators 1 '2 and in more specialized mixer programs's. These techniques require an equivalent circuit to describe the varactor. Measured or calculated information on the capacitance and current vs.
    [Show full text]