Millimeter-wave Oscillator Research Articles

The Island-Gate Varactor—A High-Q MOS Varactor for Millimeter-Wave Applications

A new accumulation MOS varactor with island-shaped poly gate layout is proposed to improve the quality factor ( Q-factor) at high frequency, which can be readily employed for CMOS-based millimeter-wave applications. Measured results up to 67 GHz show significant improvements in the Q-factor and the series resistance R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> over the conventional multi-finger MOS varactors with the same ground rule and gate area. The proposed island-gate MOS varactor is expected to improve the overall Q-factor of the LC tank of millimeter-wave oscillators.

A Flip-Chip Assembled Millimeter-Wave Oscillator Stabilized with a Micromachined Cavity on a Thin-Film Substrate

A low-cost 47 GHz microwave integrated circuit (MIC) oscillator stabilized with a micromachined cavity is presented using a thin-film substrate with a flip-chip interconnection. A GaAs pseudomorphic high electron-mobility transistor (pHEMT) was flip-chip assembled on the thin-film substrate as an active device to generate negative resistance. A micromachined cavity, which is employed to stabilize a 47-GHz MIC oscillator as a series-feedback element, is fabricated using a low-cost silicon micromachining technique and flip-chip assembled on the thin-film substrate with integrated passives. The fabricated cavity shows an unloaded Q-factor of 671 with a resonant frequency of 46.91 GHz. The cavity oscillator developed shows an output power of about 11.5 dBm and a low phase noise of -95 dBc/Hz at 1 MHz offset with an oscillation frequency at 47.06 GHz, which is a 17-dB improvement over a free running MIC oscillator. This work demonstrates the great potential of a thin-film substrate with a flip-chip interconnection for a low-cost and high-performance mm-wave system-on-package (SOP) technology.

Low-Cost, Continuously Tunable, Millimeter-Wave Photonic LO Generation Using Optical Phase Modulation and DWDM Filters

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> We report on a low-cost technique for the photonic generation of wideband continuously tunable millimeter-wave local oscillator signals. It is based on sideband filtering using an optical phase modulator and thin-film dense wavelength- division-multiplexing<?Pub _nolinebreak=""?> filters. The generated millimeter-wave signal exhibits low phase noise, and its frequency covers the <formula formulatype="inline"><tex Notation="TeX">$W$</tex> </formula>- and <formula formulatype="inline"><tex Notation="TeX">$F$</tex> </formula>-bands, from 75 to 140 GHz. </para>

Phase Noise Reduction of a Quantum Dash Mode-Locked Laser in a Millimeter-Wave Coupled Opto-Electronic Oscillator

Quantum dash active region Fabry-Perot lasers emitting at 1570 nm without an absorbing section have been evaluated as an optical source for microwave signal generation. These devices self-pulsate at 39.9 GHz with a mode-beating spectral linewidth as narrow as 10 kHz. Integration of these devices into an Opto-Electronic Oscillator has been performed, demonstrating a phase noise reduction of more than 15 dB in the low-frequency range. Moreover, the measured phase noise spectrum is well explained by a rate equation model taking into account the feedback loop.

Six-Port Interferometric Technique for Accurate $W$-Band Phase-Noise Measurements

An innovative six-port (SP) phase-noise measurement technique for millimeter-wave high-power sources is proposed in this paper. Simulation results using a 94-GHz rectangular waveguide SP circuit model validates the measurement principle for both millimeter-wave oscillators and amplifiers. Phase-noise measurement results of a 100-W extended interaction Klystron amplifier are presented and discussed. Compared to conventional methods, this new method allows accurate low-cost phase-noise measurements.

A 32-GHz Rotary Traveling-Wave Voltage Controlled Oscillator in 0.18-$\mu{\hbox{m}}$ CMOS

A millimeter-wave multiphase voltage-controlled oscillator (VCO) is presented. In order to facilitate high-frequency oscillation and to minimize the phase error caused by the device and layout mismatch, a rotary traveling-wave topology based on transmission lines with inductive loading is employed for the circuit implementation. Using a 0.18-mum CMOS process, the fabricated VCO provides half- quadrature output phases at 32 GHz. The measured output power and phase noise at 1-MHz offset are -9 dBm and -108 dBc/Hz, respectively. Operated at a supply voltage of 1.2 V, the power consumption of the proposed circuit is 54 mW.

A Millimeter-Wave CMOS LC-Tank VCO With an Admittance-Transforming Technique

A novel circuit topology suitable for millimeter-wave voltage-controlled oscillators (VCOs) is presented. With the admittance-transforming technique, the proposed VCO can operate at a frequency close to the fmax of the transistors while maintaining remarkable circuit performance in terms of phase noise, tuning range, and output power. Using a standard micrometer CMOS process, a U-band VCO is implemented for demonstration. The fabricated circuit exhibits a frequency tuning range of 1.1 GHz in the vicinity of 50 GHz. The measured output power and phase noise at 1-MHz offset are -11 dBm and -101 dBc/Hz, respectively. Operated at a supply voltage of 1.8 V, the VCO core consumes a DC power of 45 mW.

On principal impossibility of autosynchronization of an autodyne by radiation reflected from a moving target

Based on the differential equations for a single-circuit self-oscillating system subjected to its own delayed reflected radiation, expressions for analytical investigation of autodynes using phase-plane portraits and amplitude-frequency characteristics are obtained. Computation and graphical plotting of the latter characteristics are performed for the case of a moving reflecting target using different values of autodyne signal distortion. It is shown that an adequate description of the autodyne effect in microwave and millimeter-wave oscillators requires that a “phase” approach be used, which ensures a wide variation in the reflected radiation parameters, including those determining experimentally observed nonharmonic autodyne signals.

Design of a Millimeter-Wave CMOS Radiation Oscillator With an Above-Chip Patch Antenna

This brief presents a design method of a millimeter-wave CMOS radiation oscillator for broadband short-range communication. An above-chip patch antenna is proposed for the radiation oscillator. The proposed antenna has a balanced port, which makes it suitable for the direct connection of CMOS cross-coupling transistors. The properties of the antenna are analyzed by an electromagnetic field solver, and, in particular, the input resistance is discussed in detail, so that the condition of millimeter-wave oscillation is satisfied even by CMOS FETs having gains lower than GaAs FETs. Furthermore, on/off-keying modulation can be carried out using switch transistors, and two switching techniques are used to realize a large data rate. A performance of 500 Mb/s and a total efficiency of 0.12, which includes both the antenna and the circuit efficiencies, are confirmed by circuit simulation

Subharmonically Pumped Millimeter-Wave Upconverters Based on Heterostructure Barrier Varactors

A heterostructure barrier varactor subharmonic upconverter is investigated for the first time. Odd sidebands are suppressed due to the symmetric capacitance–voltage (C–V) characteristic of the varactor and high output power is possible through epitaxial stacking of barriers. The upconverter is pumped using a millimeter-wave local oscillator, and can be used as a transmission-type double-sideband suppressed carrier modulator. The initial measured conversion loss is 8–16 dB at 100 and 200 GHz. The results are significantly improved by using external impedance tuners, which is verified through both simulations and measurements.

Transmission of 37.6-GHz QPSK wireless data over 12.8-km fiber with remote Millimeter-wave local oscillator delivery using a bi-directional SOA in a full-duplex system with 2.2-km CWDM fiber ring architecture

Full-duplex 3.5-MSymb/s millimeter-wave quadrature-phase-shift-keying wireless data transmission over 12.8-km fiber transmission between a central station and base stations located on a 2.2-km coarse wavelength-division-multiplex fiber ring, with remote 40-GHz local oscillator delivery using a bidirectional semiconductor optical amplifier, is demonstrated experimentally. Successful transmission is achieved with 10.5% and 7.8% error vector magnitude values for the downlink and the uplink directions, respectively.

Efficiency and harmonic enhancement trends in GaN-based Gunn diodes: Ensemble Monte Carlo analysis

Gallium nitride can offer a high-power alternative for millimeter-wave Gunn oscillators. Hence, an ensemble Monte Carlo-based comprehensive theoretical assessment of efficiency and harmonic enhancement in n-type GaN Gunn diodes is undertaken. First, the effects of doping notch/mesa and its position within the active channel are investigated which favors a doping notch positioned next to cathode. It is then observed that the width of the notch can be optimized to enhance the higher-harmonic operation without degrading its performance at the fundamental mode. Next, the effects of dc bias and channel doping density are investigated. Both of these have more significant effects on the higher-harmonic efficiency than the fundamental one. The lattice temperature is observed to have almost no influence up to room temperature but severely degrades the performance above room temperature. As a general behavior, the variations of temperature, channel doping, and the notch width primarily affect the phase angle between the current and voltage wave forms rather than the amplitude of oscillations. Finally, the physical origin of these Gunn oscillations is sought which clearly indicates that the intervalley scattering mechanism is responsible rather than the Γ valley nonparabolicity or the effective mass discrepancy between the Γ and the lowest satellite valleys.

80-GHz differential VCO in InP SHBTs

A high frequency millimeter-wave voltage-controlled oscillator (VCO) has been designed, manufactured and tested in InP single heterojunction bipolar transistor technology. The fully integrated fundamental differential VCO features high operating frequency up to 80 GHz with low phase noise about -118 dBc/Hz at 1-MHz offset and 5% tuning range. The VCO consumes only 95-mW power at a power supply of -5 V, while providing -2 dBm single-ended output power and 1 dBm for differential output power. The die size is 0.28 mm/sup 2/.

Gunn oscillations in GaN channels

Gallium nitride with its high negative differential mobility threshold is an appealing material for high power millimetre-wave oscillators as a Gunn diode. By means of extensive ensemble Monte Carlo simulations, the dynamics of large-amplitude Gunn domain oscillations from 120 GHz to 650 GHz is studied in detail. Their operations are checked under both impressed single-tone sinusoidal bias and external tank circuit conditions. The width of the doping notch is observed to enhance higher harmonic efficiency at the expense of the fundamental frequency up to a critical value, beyond which sustained Gunn oscillations cease. The degeneracy effects due to the Pauli exclusion principle are also considered, but their effects are seen to be negligible within the realistic bounds of the Gunn diode operation.

Recent Trend of Millimeter-Wave Access Systems

This paper describes the recent trend of millimeter-wave wireless access systems which utilize the advantages of millimeter-waves. The fixed wireless access systems are first discussed and newly developed testbed at Yokosuka city area for broadband transmission is introduced. Then three promising short distance wireless access systems using 60-GHz frequency are discussed. The first one is on video transmission in the house, the second on vertically -connected link for the apartment infrastructure, and the third on wireless personal area ad-hoc system. Lastly millimeter-wave self-heterodyne transmission method is briefly introduce which can decrease the complex and cost of millimeter-wave local oscillators.

Ultra-wide-band traveling-wave photodetectors for photonic local oscillators

This paper reviews recent advances in the development of high-speed 1.55-μm traveling-wave p-i-n photodetectors (TWPD) for photonic millimeter-wave and submillimeter-wave local oscillators. We first discuss the basic physics and performances of high-speed 1.55-μm TWPD. Next, we present a frequency-domain optical-heterodyne measurement technique for ultra-wide-band characterization of the TWPD and photonic transmitter modules within the frequency range from almost dc up to more than 1 THz. We further demonstrate ultra-wide-band (0.02-0.7 THz) photonic transmitter modules consisting of a high-speed TWPD coupled to a broad-band bow-tie antenna as well as a narrow-band 0.46-THz photonic transmitter module producing output power levels sufficient to operate a superconductor-insulator-superconductor (SIS) astronomical receiver under optimum conditions. Finally, we will report on ultra-wide-band (0.06-1 THz) photonic transmitter modules consisting of high-speed TWPDs coupled to various rectangular metallic waveguides (WR10, WR8, and WR5).

A 52 GHz VCO with low‐phase noise implemented in SiGe BiCMOS technology

AbstractA fully integrated 52‐GHz millimeter‐wave LC voltage‐controlled oscillator (VCO) with −106 dBc/Hz phase noise at 600‐kHz offset frequency and 0.93‐GHz tuning range is reported in this paper using IBM BiCMOS‐6HP technology. The output voltage swing of the VCO is about 0.4 Vp‐p for the complementary cross‐coupled topology with a buffer. A bipolar device is used as the tail transistor to constantly supply a current in order to preserve the oscillation of the VCO. The parasitics due to the interconnected metals are extracted from the layout, and the effects of those parasitics on the VCO's performance are investigated. Based on these analyses, an optimized layout of the complementary VCO is obtained, and the pre‐layout and post‐layout simulations are compared and presented. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 414–418, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11235

Broadband suppression of phase-noise with cascaded phase-locked-loops for the generation of frequency ramps

Abstract. The generation of analogue frequency ramps with non-fractional phase-locked-loops (PLL) is a cost effective way of linearising varactor controlled oscillators (VCO). In case that the VCO shows a high phase-noise level, a single non-fractional PLL is not able to suppress the phase-noise of the VCO sufficiently. The reason for this is the limited loopbandwidth of the PLL. In the field of precise measurements a high phase-noise level is mostly not tolerable. Examples of VCO-types with an extremely high phase noise level are integrated millimetre wave oscillators based on GaAs-HEMT technology. Both, a low quality factor of the resonator and a high flicker-noise corner frequency of the transistors are the main reason for the poor phase-noise behaviour. On the other hand this oscillator type allows a cost effective implementation of a millimetre-wave VCO. Therefore, a cascaded two-loop structure is presented that is able to linearise a VCO and additionally to reduce its phase-noise significantly.

Microwave and millimeterwave oscillator developments at the Johannes Kepler University

This contribution reviews the research work performed at the Johannes Kepler University of Linz, Austria, on the development of oscillators for the microwave and millimeter wave frequency range. This work, performed by the Microelectronics Institute and the Institute for Communications and Information Engineering, covers the range from low GHz frequencies up to 61 GHz and is devoted to applications like mobile communications and sensing. The active devices are based on gallium arsenide (GaAs), silicon germanium (SiGe), and Silicon (Si) and include Gunn-devices, bipolar transistors, and CMOS-technology.

Hybrid millimeter-wave push-push oscillators using silicon-germanium HBTs

Push-push design has proven to be an efficient way to extend the usable frequency range of active devices for oscillator applications. In this paper, the basic principles of push-push oscillator design are explained and various possibilities to realize this concept are shown. Several examples of hybrid millimeter-wave push-push oscillators using SiGe HBTs as active devices are discussed. Details on large-signal modeling of the SiGe HBTs using both a vertical bipolar integrated-circuit model, as well as a customized large-signal model are given. Measured key performance data of microstrip resonator oscillators at 57 and 58 GHz are output power levels of +1 dBm and single-sideband phase-noise figures (1-MHz offset from carrier) of -106 and -108 dBm/Hz, respectively. For the dielectric-resonator oscillators, a maximum output power of -8 dBm and an optimum phase noise of -112 dBc/Hz (-14-dBm output power), as well as a mechanical tuning range of 500 MHz were measured.