Subharmonically Pumped Research Articles

Compact low-repetition-rate femtosecond optical parametric oscillators enabled by Herriott cells

We report the design and characterization of a femtosecond optical parametric oscillator containing an intracavity Herriott cell. Pumped by a 49.16-MHz Yb:fiber laser, the signal wavelength could be tuned over 1440-1530 nm, with the Herriott cell containing 81% of the free-space cavity length required for synchronous operation. We also report a 12.29-MHz OPO using a sub-harmonic pumping approach, extending the Herriott cell OPO concept to low-repetition-rate cavities.

A Phase Conjugator Based on Fourth-Order Subharmonically Pumped Mixers

A Phase Conjugator Based on Fourth-Order Subharmonically Pumped Mixers

Sliding, vibrating and swinging droplets on an oscillating fibre

We study experimentally the dynamics of a water droplet on a tilted and vertically oscillating rigid fibre. As we vary the frequency and amplitude of the oscillations the droplet transitions between different modes: harmonic pumping, subharmonic pumping, a combination of rocking and pumping modes, and a combination of pumping and swinging modes. We characterize these responses and report how they affect the sliding speed of the droplet along the fibre. The swinging mode is explained by a minimal model making an analogy between the droplet and a forced elastic pendulum.

A GaN-on-Si passive upconversion mixer for Ku-band applications

This paper showcases a passive single side-band (SSB) subharmonically pumped (SHP) GaN on Si mixer intended for operation in the Ku band. A passive topology has been selected in order to test the viability of these kinds of designs for GaN applications. By utilising the SSB SHP mixer, it is possible to reduce the energy consumption of a complete transmission system implementation. Two techniques to enhance the performance of the mixer are tested. First, the quasi-lumped method has been employed to reduce the size of the stubs needed to implement the mixer topology. Secondly, octagonal tapered inductors were used to obtain higher quality factors and narrow the frequency response of the lumped-element hybrids. The final design occupies an area of 2720μm×1514μm, including pads. Measurements show a performance in line with the simulations, with a slight increase in its losses with respect to the simulation results. Through the measurement of a transistor of the technology, it is demonstrated that this deviation is caused by the variability of the process and its low technology readiness level (TRL). The results are very promising and prove the advantages of implementing passive mixers for high-frequency applications in GaN on Si technologies.

PRINCIPLES OF DEVELOPMENT OF THE TERAHERTZ BAND TELECOMMUNICATION SYSTEM BASED ON THE TECHNOLOGY OF HARMONIC SIGNAL AS THE INFORMATION CARRIER

Physical principles of introduction and reproduction of the information transmitted using the harmonic signal as the information carrier, are analyzed. Based on the performed theoretical calculations confirmed by the results of modeling, there are formed the principles and rules of determining optimal parameters of the ultra-wideband terahertz frequency range communication system on the basis of the technology of electronics using the harmonic signal as the information carrier. The necessity of using the terahertz frequency band while deploying future super high throughput rate telecommunication systems is reasoned. Analysis of the state-of-the-art problem is performed, the direction of research is selected and the mission is set with regards to creation of the terahertz band broadband access telecommunication system with the Gigabit throughput rate within the operating frequencies range of 130…134 GHz. Characteristics of the signal propagation path and defining of the signal losses under the conditions of the terahertz frequency band radio relay system operation are analyzed. On the basis of the analysis performed it is shown that operation of radio relay links in the terahertz band allows practically disregarding the refraction and interference of the electromagnetic waves reflected from the obstacles in the radio signal propagation domain that occurs primarily under the conditions of a dense urban building. The domains of the terahertz band frequencies, which are most of all suitable for use in the radio relay communication lines, are determined. Physical modeling of the super high data rate former is performed on the basis of the multifrequency multiplexing of the OFDM-modulated digital flows, testing at the experimental stand and the optimization aimed at attaining of the maximal throughput capacity of the channel used for transmission of the digital information of the flow are fulfilled in the Ethernet format using the developed software means. The created software and hardware means allowed attaining, for the first time, the general channel data rate of up to 1.2 Gbps at the full duplex. There are developed the block circuit diagram of the system transceiver path – the frequency converters with subharmonic pumping, the heterodyne using a high-stability setting quartz oscillator with the subsequent circuitry of multiplying and amplifying cascades, the bandpass filter using a thin metal plate in the E-plane of the 1.6×0.8 mm waveguide channel, and the horn-lens antenna.

THz limb sounder (TLS) for lower thermospheric wind, oxygen density, and temperature

AbstractNeutral winds are one of the most critical measurements in the lower thermosphere and E region ionosphere (LTEI) for understanding complex electrodynamic processes and ion‐neutral interactions. We are developing a high‐sensitivity, low‐power, noncryogenic 2.06 THz Schottky receiver to measure wind profiles at 100–140 km. The new technique, THz limb sounder (TLS), aims to measure LTEI winds by resolving the wind‐induced Doppler shift of 2.06 THz atomic oxygen (OI) emissions. As a transition between fine structure levels in the ground electronic state, the OI emission is in local thermodynamic equilibrium (LTE) at altitudes up to 350 km. This LTE property, together with day‐and‐night capability and small line‐of‐sight gradient, makes the OI limb sounding a very attractive technique for neutral wind observations. In addition to the wind measurement, TLS can also retrieve [OI] density and neutral temperature in the LTEI region. TLS leverages rapid advances in THz receiver technologies including subharmonically pumped (SHP) mixers and Schottky‐diode‐based power multipliers. Current SHP Schottky receivers have produced good sensitivity for THz frequencies at ambient environment temperatures (120–150 K), which are achievable through passively cooling in spaceflight. As an emerging technique, TLS can fill the critical data gaps in the LTEI neutral wind observations to enable detailed studies on the coupling and dynamo processes between charged and neutral molecules.

V-Band High Data-Rate I/Q Modulator and Demodulator With a Power-Locked Loop LO Source in 0.15-/spl mu/m GaAs pHEMT Technology

A wideband sub-harmonically pumped (SHP) modulator and demodulator fabricated in 0.15-μm GaAs pseudomorphic high electron-mobility transistor technology are demonstrated in this paper. The chip is appropriate for emerging 60-GHz multi-gigabit communication applications. Digital modulation degradation resulting from in-phase/quadrature mismatch is effectively minimized by the proposed power-locked loop system. By overcoming the bandwidth limitations and quadrature errors in amplitude and phase, the sideband suppression ratio exhibits broadband performance with the feedback mechanism. By using the SHP mixer structure, the dc offset problem is mitigated because of decreased 2× local oscillator leakage. In addition, sub-circuit design considerations and feedback stability are described in this paper. The SHP modulator and demodulator demonstrate flat conversion-gain responses of -14 ±2 dB and -14 ±1 dB, respectively, from 51 to 68 GHz. Properties of multi-gigahertz modulation and demodulation bandwidths show the potentials for gigabit applications. The amplitude and phase imbalances are restricted within 0.3 dB and 5° (±2.5°), respectively, regardless of modulation or demodulation. High data-rate digital modulation and demodulation are successfully performed through 16-QAM and 64-QAM schemes within four channels of the IEEE 802.15.3c standard with outstanding error vector magnitude performances.

Miniature single-sideband subharmonically-pumped 60 GHz direct upconverter in a uniplanar GaAs pHEMT technology using inductive and capacitive loading techniques

This paper presents a novel, compact, single-sideband (SSB) subharmonically-pumped (SHP) direct upconverter developed in a uniplanar 0.18 μm GaAs technology. A total of 100 MHz in-phase and quadrature signals directly modulate the second harmonic of a 30 GHz carrier signal, producing a 60.1 GHz output. Two pairs of antiparallel diodes reduce feed-through of the 30 GHz local oscillator (LO) signal to the mixer's RF output. Novel structures patterned in the center conductor of a coplanar waveguide (CPW) provide matching and size-reduction simultaneously. The 2.1mm2 circuit also uses a miniaturized Wilkinson divider based on asymmetric coplanar stripline and a standard CPW 90° coupler. The SSB SHP direct upconverter exhibits a conversion loss of 10 dB, a lower-sideband rejection of 15 dB and 2fLO suppression of approximately 25 dB over a wide frequency range from 52–61 GHz.

E-Band Wideband MMIC Receiver Using 0.1 µm GaAs pHEMT Process

In this paper, the implementations of a gallium arsenide (GaAs) pseudomorphic high electron mobility transistor process for a low noise amplifier (LNA), a subharmonically pumped (SHP) mixer, and a single-chip receiver for 70/80 GHz point-to-point communications are presented. To obtain high-gain performance and good flatness for a 15 GHz (71 GHz to 86 GHz) wideband LNA, a five-stage input/output port transmission line matching method is used. To decrease the package loss and cost, 2nd and 4th SHP mixers were designed. From the measured results, the five-stage LNA shows a gain of 23 dB and a noise figure of 4.5 dB. The 2nd and 4th SHP mixers show conversion losses of 12 dB and 17 dB and input P1dB of -1.5 dBm to 1.5 dBm. Finally, a single-chip receiver based on the 4th SHP mixer shows a gain of 6 dB, a noise figure of 6 dB, and an input P1dB of -21 dBm.

NUMERICAL STUDY OF BEHAVIOURAL SUB-HARMONICALLY PUMPED MIXER IN A NOVEL STRUCTURE

A Sub Harmonically Pumped (SHP) mixer suitable for direct conversion receiver in 3G mobile frequency band is presented. This mixer is realized with N anti-parallel diode pairs (APDPs) and designed in self-biased structure to obtain minimum noise flgure and conversion loss. In this paper, a simultaneous signal and noise analysis CAD routine to analyze a circuit consists of Arbitrary Number of anti- parallel diode pairs in self-biased structure is proposed. Then the results of this CAD routine are conflrmed with other method. The mixer is optimized to obtain a maximally ∞at conversion gain and minimum Noise Figure over various LO powers. The proposed CAD is used to obtain the optimum number of APDPs. Also the optimum self-biased resistance and output load are calculated.

35–65-GHz CMOS Broadband Modulator and Demodulator With Sub-Harmonic Pumping for MMW Wireless Gigabit Applications

Sub-harmonic modulator and demodulator are presented in this paper using 0.13-mum standard CMOS technology for millimeter-wave (MMW) wireless gigabit direct-conversion systems. To overcome the main problem of local oscillator (LO) leakage in direct-conversion systems, the sub-harmonically pumped scheme is selected in this mixer design. An embedded four-way quadrature divider is utilized in the sub-harmonic Gilbert-cell design to generate quadrature-phases LO signals at MMW frequency. For broadband applications, a broadband matching design formula is provided in this paper to extend the operational frequency range from 35 to 65 GHz. To improve the flatness of conversion loss at high frequency, high-impedance compensation lines are incorporated between the transconductance stage and LO switching quad of the Gilbert-cell mixer to compensate the parasitic capacitance. The sub-harmonic modulator and demodulator exhibit 6 plusmn1.5 dB and 7.5 plusmn1.5 dB measured conversion loss, respectively, from 35 to 65 GHz. For MMW wireless gigabit applications, the gigabit modulation signal test is successfully performed through the direct-conversion system in this paper. To our knowledge, this is the first demonstration of the MMW CMOS sub-harmonic modulator and demodulator that feature broadband and gigabit applications.

A Miniature $Q$-Band Balanced Sub-Harmonically Pumped Image Rejection Mixer

This work presents a miniature Q-band balanced single side-band sub-harmonically pumped image rejection diode mixer (SHIRM) using a compact Marchand dual balun design. The SHIRM is realized employing four anti-parallel diode pairs for frequency mixing, a Lange coupler for radio frequency (RF) signal input, and a reduced size three-conductor-line Marchand dual balun for local oscillator pumping. The length of three-conductor-line dual balun is reduced by 81% after shunting two lumped capacitors at the center conductor. The measured results exhibit a minimum conversion loss of 8.6 dB, a maximum image rejection ratio of 22 dB, all ports isolation better than 37 dB, and an input 1-dB compression point of 2.5 dBm at RF bandwidth of 40.5 to 43.5 GHz and fixed intermediate frequency of 2.4 GHz. The chip area is very compact, only 1 times 0.84mm2

Size Reduction of a MMIC Direct Up-Converter at 44 GHz in Multilayer CPW Technology Using Thin-Film Microstrip Stubs Loading

This paper proposes a novel compact multilayer 44.5-GHz coplanar waveguide (CPW) single-sideband (SSB) subharmonically pumped (SHP) mixer for direct up-conversion GaAs monolithic microwave integrated circuit. It uses previously developed thin-film microstrip (TFMS) and CPW structures for capacitive and inductive loading techniques to drastically reduce its size. The SSB SHP mixer uses 50-MHz in-phase and quadrature signals to directly modulate the second harmonic of a 22.25-GHz carrier to produce the required 44.55-GHz RF output. Two pairs of antiparallel diodes reduce feedthrough of the fundamental 22.25-GHz signal to the RF output while novel CPW/TFMS-based structures provide matching. This 1.2times1.5 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> chip uses a lumped Wilkinson divider as a local-oscillator divider and a previously developed reduced size 90deg coupler. The SSB SHP mixer acts as an up-converter with a measured conversion gain of -10plusmn1 dB and the lower sideband suppression is greater than 23 dB across the RF bandwidth of 43.5-45.5 GHz. Additionally, it is shown that the RF port return loss is better than 20 dB, and 2timesf <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LO</sub> was suppressed by 21 dB over the same band. The circuit also does not require any dc bias. Compared to the conventional SSB SHP mixer, a 70% reduction in circuit area was achieved with better performances

Parametric Conversion Using Custom MOS Varactors

The possible role of customized MOS varactors in amplification, mixing, and frequency control of future millimeter wave CMOS RFICs is outlined. First, the parametric conversion concept is revisited and discussed in terms of modern RF communications systems. Second, the modeling, design, and optimization of MOS varactors are reconsidered in the context of their central role in parametric circuits. Third, a balanced varactor structure is proposed for robust oscillator frequency control in the presence of large extrinsic noise expected in tightly integrated wireless communicators. Main points include the proposal of a subharmonic pumping scheme based on the MOS varactor, a nonequilibrium elastance-voltage model, optimal varactor layout suggestions, custom 0.13 µm-CMOS varactor design and measurement, device-level balanced varactor simulations, and parametric circuit evaluation based on measured device characteristics.

A W-band subharmonically pumped monolithic GaAs-based HEMT gate mixer

A W-band high electron mobility transistor (HEMT) subharmonically pumped (SHP) gate mixer is designed with fixed LO frequency operation. it is fabricated on a 4-mil substrate using 0.15-/spl mu/m GaAs pHEMT monolithic microwave integrated circuit (MMIC) process. the on-wafer measurement results show that the best conversion loss is about 4.7 dB in the W-band, as a 11-dbm 42-GHz low observable (LO) signal is pumped. To our knowledge, this is the first result on low conversion-loss W-band MMIC SHP HEMT gate mixer.

Novel subharmonically pumped mixer incorporating dual-band stub and in-line SCMRC

A subharmonically pumped (SHP) mixer with very low conversion loss is proposed. The mixer employed the newly developed spiral compact microstrip resonant cell (SCMRC) and compact dual-band stub (DBS). Incorporating the in-line SCMRC and DBS into a second SHP mixer, we can provide proper terminations for the IF, RF, and local-oscillator (LO) signal simultaneously in addition to all major unwanted mixing products, leading to a unique low conversion-loss design. Our SHP mixer with a measured 3.9-dB single-sideband (SSB) down-conversion loss at 11.6-GHz RF signal outperforms typical designs of 8-12 dB, and represents a state-of-the-art performance for a planar X-band harmonic mixer. With a broad-band operation, our mixer shows an SSB down-conversion loss of less than 8.2 dB from 9 to 12.8 GHz. Moreover, the measured LO-RF isolation is better than 45 dB for LO frequency ranges of 4-5.8 GHz. Large-signal two-tone measurements reveal an excellent linear response of the working prototype, showing 7.5 dBm and 52 dB for the 1- dB power compression point and spurious-free dynamic range, respectively.

A 78-114 GHz monolithic subharmonically pumped GaAs-based HEMT diode mixer

A W-band subharmonically pumped (SHP) diode mixer is designed for fixed LO frequency operation. It is fabricated on a 4-mil substrate using 0.15 /spl mu/m GaAs PHEMT MMIC process. The on-wafer measurement results show that the conversion loss is about 10 to 14 dB across the W band, as a 10 dBm 48 GHz LO signal is pumped. To our knowledge, this is the state-of-the-art result on low-conversion-loss wideband MMIC SHP diode mixer. The packaged module measurement shows a similar result. Both the simulation and measurement results are shown to be in good agreement.

Millimeter-wave-band amplifier and mixer MMICs using a broad-band 45° power divider/combiner

This paper demonstrates millimeter-wave-band amplifier and mixer monolithic microwave integrated circuits (MMIC's) using a broad-band 45/spl deg/ power divider/combiner. At first, we propose a broad-band 45/spl deg/ power divider/combiner, which combines a Wilkinson divider/combiner, 45/spl deg/ delay line, and 90/spl deg/ short stub. A coupling loss of 4.0/spl plusmn/0.2 dB and a return loss and an isolation of more than 19 dB with 45/spl plusmn/1/spl deg/ phase difference was obtained from 17 to 22 GHz for the fabricated K-band MMIC 45/spl deg/ power divider/combiner. Next, a parallel amplifier using the broad-band 45/spl deg/ power divider/combiner, which can be used in a power-combining circuit configuration requiring no isolator, is shown. Comparing the transmitter intermodulation generated in the parallel amplifier using the broad-band 45/spl deg/ power divider/combiner and that generated in the one using the conventional type, the broad-band suppression effect was confirmed. Finally, an application of the broad-band 45/spl deg/ power divider/combiner to a single-sideband (SSB) subharmonically pumped (SHP) mixer requiring no IF switch is shown. In an RF frequency range from 22.89 to 26.39 GHz, the fabricated K-band MMIC mixer achieved (for up-conversion) the good results of more than -13-dB conversion gain and more than 24-dB image-rejection ratio. These contribute significantly to the miniaturization of millimeter-wave communication equipment.

Planar diode solid-state receiver for 557 GHz with state-of-the-art performance

The design and performance of a subharmonically pumped (SHP) 557-GHz mixer driven by a solid-state local oscillator (LO) are reported. Whisker contacts are not required as both the mixer and LO utilize planar Schottky devices. A measured mixer noise temperature of 2100-K double sideband (DSB) with a conversion loss of 8.9 dB has been achieved at room temperature. The mixer exhibits broad intermediate frequency (IF) bandwidth with measured DSB noise temperatures below 3400 K in the band from 1.5 to 17 GHz. An external 6-18-GHz amplifier has been added to the output of the mixer, and measured receiver noise temperatures below 7300 K have been measured across the IF band. The results are believed to represent state-of-the-art performance for a room-temperature broad-band solid-state receiver at this frequency.

A planar quasi-optical mixer using a folded-slot antenna

A quasioptical mixer using only planar structures such as coplanar-waveguide and slotline is presented. The mixer, which can be scaled for millimeter-wave applications and placed on a substrate lens, uses orthogonal modes in a folded-slot antenna to achieve intrinsic RF/LO isolation without BF filtering or subharmonic pumping. The folded-slot balanced mixer was fabricated on RT/Duriod and obtained a minimum isotropic conversion loss of 1.2 dB at 11.6 GHz. Numerical integration of full two-dimensional antenna patterns yielded an antenna directivity of 7 dB, corresponding to a single side-band (SSB) mixer conversion loss of 8.2 dB. The mixer demonstrated -18 dB RF/IF isolation and -30 dB LO/IF isolation. >