LO Power Requirement Research Articles

Efficiency Assessment of Traditional GaAs and Low-Power InGaAs Schottky Diodes in Full-Band Mixers at 0.3 THz

In this paper, we present and compare two different full-band WR3.4 Sub-Harmonic Mixers (SHMs), featuring traditional GaAs and the novel low-barrier InGaAs discrete diodes. In this study, an Active Multiplier Chain (AMC) is used as a Local Oscillator source, which provides peak powers beyond 20 mW. The GaAs mixer presents Single-Sideband (SSB) Conversion Loss (CL) of 10 dB and Double-Sideband (DSB) Noise Temperature (NT) of 3000 K across the entire RF and IF bands when an LO power of 6–10 mW is applied. The low-barrier mixer featuring the new and improved batch of InGaAs diodes performs SSB Conversion Loss of 15 dB and DSB Noise Temperature of 9000 K, using LO powers of 0.5 mW. In this work, a comparison of the CL and NT of both mixers is carried out, highlighting the excellent performances of GaAs diodes and the minimum LO power requirements needed by InGaAs counterparts, as well as future perspectives in InGaAs mixer performances. The mixers and diodes were fully designed, fabricated, and tested at ACST GmbH.

86 to 94GHzlow lossCMOSbalanced resistive mixer using an asymmetric broadside coupler and delay lines

AbstractAn 86 to 94 GHz balanced resistive mixer (BRM) is presented using a 65 nm complementary metal‐oxide‐semiconductor (CMOS) process. We minimize parasitic losses which are serious at high frequency by adopting symmetric transistor structures. A low loss 180° hybrid is implemented using an asymmetric broadside coupler and delay lines. This allows low‐loss implementation of 86 to 94 GHz BRMs, which represent a conversion loss of 10.3 to 13.0 dB from 86 to 94 GHz of RF frequencies. The balanced designs produce LO‐to‐RF isolations of 32 to 36 dB from 87 to 93 GHz. The proposed CMOS BRM shows competitive results when compared to GaAs‐ or InP‐based balanced resistive mixers having moderate LO power requirements.

Dielectric Constant and Loss Tangent of Silicon at 700–900 GHz at Cryogenic Temperatures

Quasi-optical superconducting hot-electron bolometer (HEB) mixers have shown a competitive sensitivity at a frequency slightly lower than 1 THz when compared to superconducting SIS mixers. The advantage of low LO power requirement makes superconducting HEB mixers, especially suitable for array application. The far-field beam pattern, as well as coupling efficiency of quasi-optical superconducting HEB mixers, depends strongly upon the lens shape and the dielectric constant of the lens material. Therefore, in this letter we precisely measured the dielectric constant and loss tangent of high resistivity silicon at 4, 77, and 300 K in the frequency range of 700–900 GHz where many important molecular lines located. The measurements are performed by employing a quasi-optical vector network analyzer with a dynamic range as high as 110 dB to ensure high precision measurement. In addition, the dielectric constant of high-density polyethylene (HDPE) and polymethylpentene (TPX/PMP) are also measured since they are widely used in terahertz quasi-optical system.

80-GHz-band low-power sub-harmonic mixer IC with a bottom-LO-configuration in 130-nm SiGe BiCMOS

In this paper, a W-band (80 GHz) sub-harmonic mixer (SHM) IC is designed, fabricated and measured in 130-nm SiGe BiCMOS technology. The presented SHM IC makes use of a common emitter common collector transistor pair structure with a bottom-LO-configuration to decrease the LO power requirement and a tail current source to flatten the conversion gain. On-chip Marchand balun is designed for W-band on-wafer measurements. The SHM IC presented in this paper has exhibited a conversion gain of 3.9 dB at 80 GHz RF signal with an LO power of only −7 dBm at 39.5 GHz. The mixer core consumes only 0.68 mA at a supply voltage of 3.3 V.

Low conversion loss 94 GHz CMOS resistive mixer

A 94 GHz CMOS resistive mixer is presented using the 65 nm CMOS process. Parasitic losses which are serious at high frequencies are minimised by adopting the optimised transistor size and symmetric transistor layouts as well as a scaled-down 65 nm CMOS technology, which contribute to reducing the conversion loss at 94 GHz by 2–3 dB, the conversion loss being 8.8–9.2 dB from 87 to 94 GHz of RF frequencies with an LO power of <7.6 dBm. To the best of the authors' knowledge, this is the best performance of CMOS resistive mixers operating in the frequency band of more than 90 GHz. The results also are competitive when compared with GaAs-based resistive mixers having moderate LO power requirements and a reasonable noise figure.

A 7–8.5 GHz High Performance MMIC HTS Josephson Mixer

A low-loss, low power consumption monolithic high-temperature superconducting (HTS) Josephson junction mixer at 7-8.5 GHz is presented. The mixer consists of a HTS YBa2Cu3O7-x (YBCO) bandpass filter for RF input, a lowpass filter for IF output and a LO resonator integrated with a single Josephson junction. All the passive and active devices are fabricated on a 20 mm×10 mm MgO substrate. Measurement result shows a conversion gain of -7 dB at 40 K, and -4.7 dB at 20 K. The IF output versus the RF input exhibits a wide linear range of conversion gains. The mixer has an extremely low LO power requirement at -32 dBm and a 50 nW power consumption.

FMCW 레이더용 W-대역 단일칩 수신기 MMIC

본 논문에서는 0.15 μm GaAs pHEMT 기술을 이용하여 FMCW(Frequency-modulated continuous-wave) 레이더용 W-band 단일칩 수신기 MMIC를 구현하였다. 제작된 수신기는 4 단 저잡음 증폭기, 하향 변환 혼합기, 3 단 LO 버퍼 증폭기로 구성되어 있다. 수신기의 저잡음 특성과 선형성 향상을 위해 저잡음 증폭기의 성능을 최적화시켰다. 혼합기는 선형성 특성 및 낮은 IF 주파수에서 저잡음 특성을 위하여 저항성 혼합기로 설계하였다. W-대역에서 혼합기를 구동시키기 위해서는 높은 LO 입력이 요구되므로 추가적인 LO 버퍼 증폭기를 설계하였다. 단일칩 수신기의 측정 결과, RF 주파수 f0 GHz, LO 입력 전력 -1 dBm, 그리고, IF 주파수 100 MHz에서, 6.2 dB의 변환 이득, 5.0 dB의 잡음 지수, 그리고, -12.8 dBm의 1-dB 이득 감쇄 입력 전력(P1dB,in) 등의 우수한 특성을 얻었다.

A 77 GHz Low LO Power Mixer With a Split Self-Driven Switching Cell in 65 nm CMOS Technology

A low LO power mixer with high gain by using a split self-driven switching cell for automotive applications at 77 GHz is presented. By splitting the switching cell, the required LO power is reduced and the VCO has less capacitive loading. The mixer has a peak conversion gain of 6.8 dB and the input 1 dB compression point is 7 dBm at LO power of 5 dBm. The chip is fabricated in 65 nm CMOS technology and the chip size including a Marchand balun is 790 μm × 590 μm. The total power consumption is 3 mW from a 1.2 V supply.

60-GHz Dual-Conversion Down-/Up-Converters Using Schottky Diode in 0.18 $\mu{\hbox {m}}$ Foundry CMOS Technology

Due to the benefits of Schottky diodes, 0.18-μm CMOS technology is being promoted for millimeter wave applications. In this paper, 60-GHz dual-conversion down-/up-converters using Schottky diodes are realized by using 0.18-μm foundry CMOS technology. A CoSi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -Si Schottky diode, fabricated on a lower doped N-well by blocking the threshold voltage adjustment implant, has a lower reverse leakage current and a better ideality factor. Thus, it is ideal for the 60-GHz sub-harmonic mixer design. Two new types of Schottky-diode mixers, a down-conversion sub-harmonic mixer with a dual-band lump-distributed phase-inverter rat-race coupler and an up-conversion sub-harmonic mixer with a trifilar transformer, are realized and employed at the high-frequency conversion stage of the dual-conversion architecture to achieve small size and broadband isolations. The silicon-based Schottky diode with a low turn-on voltage offers great advantage in LO pumping power, especially for an antiparallel diode pair structure. In our Schottky-diode sub-harmonic mixers, the required LO power is only 1 dBm. The dual-conversion down-converter achieves 5-dB conversion gain and 19 dB noise figure under <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Vdd</i> =2.5 V and <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Idd</i> =22 mA, and the dual-conversion up-converter, with <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Vdd</i> =2.5 V and <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Idd</i> =26 mA, attains greater than 40-dB sideband rejection and -1 dB conversion gain over the whole 60-GHz bandwidth.

Terahertz Superconducting Hot Electron Bolometer Heterodyne Receivers

We highlight the progress on NbN hot electron bolometer (HEB) mixers achieved through fruitful collaboration between SRON Netherlands Institute for Space Research and Delft University of Technology, the Netherlands. This includes the best receiver noise temperatures of 700 K at 1.63 THz using a twin-slot antenna mixer and 1050 K at 2.84 THz using a spiral antenna coupled HEB mixer. The mixers are based on thin NbN films on Si and fabricated with a new contact-process and-structure. By reducing their areas HEB mixers have shown an LO power requirement as low as 30 nW. Those small HEB mixers have demonstrated equivalent sensitivity as those with large areas provided the direct detection effect due to broadband radiation is removed. To manifest that a HEB based heterodyne receiver can in practice be used at arbitrary frequencies above 2 THz, we demonstrate a 2.8 THz receiver using a THz quantum cascade laser (QCL) as local oscillator.

NbN Hot Electron Bolometer Mixers: Sensitivity, LO Power, Direct Detection and Stability

We demonstrate that the performance of NbN lattice cooled hot electron bolometer mixers depends strongly on the interface quality between the bolometer and the contact structure. Both the receiver noise temperature and the gain bandwidth can be improved by a factor of 2 by cleaning the interface and adding an additional superconducting interlayer to the contact pad. Using this we obtain a double sideband receiver noise temperature of 950 K at 2.5 THz and 4.3 K, using a 0.4/spl times/4 /spl mu/m HEB mixer with a spiral antenna. At the same bias point, we obtain an IF gain bandwidth of 6 GHz. To comply with current demands on THz mixers for use in space based receivers we reduce the device size to 0.15/spl times/1 /spl mu/m and use a twin slot antenna. We report measurements of the noise temperature, LO power requirement, stability and the direct detection effect, using a mixer with a 1.6 THz twin slot antenna and a 1.462 THz solid state LO source with calibrated output power.

Millimeter‐wave down‐converter conversion gain performance enhancement

AbstractThe influence of via hole inductance on millimeter‐wave single‐ended pHEMT gate‐mixer down‐converter conversion gain is examined by a closed formula and by measurement. It is shown that feedback inductance acts as a voltage divider, reducing the conversion gain and increasing the LO power requirements. Analytical considerations presented in the paper predict that this effect can reduce the conversion gain by up to 9 dB. Additionally, a method to minimize the influence of via hole inductance on mixer performance is presented. Two circuits, one with and one without resonating stubs, have been manufactured and tested. The new circuit exhibits 3.5 dB more conversion gain than the classical topology, RF 65.3 GHz, nominal IF 1.3 GHz. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 32: 399–400, 2002.

A Novel LO Power Injection Method for SIS Mixers

We propose a novel LO power injection method developed for SIS mixers in this paper. Based on the feature of extremely small LO power requirements of SIS quantum mixing, the new method fulfills SIS pumping through a DC/IF route based built-in LO path, which is composed of an additional LO waveguide and the existing microstrip choke filter on the junction substrate. With the new method, traditional external LO diplexers(e.g., crossguide-couplers or beamsplitters) become unnecessary, resulting in a lower loss, compact, and stable receiver system. Experiments at 110- and 230 GHz bands have shown that the present method is efficient in coupling sufficient pumping power to SIS junctions from general LO sources, and the receiver sensitivities have a further improvement of about 10 K. We expect this method is also able to be applied into submillimeter wave band for SIS mixers.

X‐Band MMIC Active Mixers

In this paper two active MMIC mixers for RF front‐end applications are described. A down‐converter that converts an RF signal (fRF = 10.45 GHz) into an IF signal (fIF = 0.95 GHz) using an LO signal (fLO = 9.5 GHz) and an up‐converter that performs the opposite process have been fabricated. The down‐converter is designed using the topology of a dual‐gate pHEMT, while the up‐converter is implemented in the form of a double balanced mixer using the topology of the Gilbert cell and the occupied areas are approximately 0.78 mm2 and 3.86 mm2 , respectively. Both mixers present conversion gain, very low input and output return losses, very good isolation between all of their ports and the required LO power is quite low, while the up‐converter contains on chip, except for the dc‐bias and matching sub‐circuits, the required LO and RF baluns. Both circuits have been fabricated using the H‐40 process of GEC‐Marconi. Section 1 presents fundamentals on mixer theory and mixer design while in Section 2 the characteristics of H‐40 process are described. In Section 3 and in Section 4 the designing, the simulated and the measured results of the down‐converter and the up‐converter are presented, respectively.

A novel biased anti-parallel Schottky diode structure for subharmonic mixing

Subharmonically pumped mixers using zero-biased anti-parallel Schottky diode pairs produce good results, but require a larger LO power than biased Schottky diodes. Presented here is a novel planar-diode anti-parallel pair that allows independent biasing of the two diodes. This diode pair is integrated into a quasi-optical wideband receiver and the RF measurements on a 1.2-/spl mu/m anode diameter pair show a reduced LO power requirement at 180 GHz by a factor of 2 to 3 with a similar DSB conversion loss and noise temperature (9.7 dB and 1850 K) to an unbiased Schottky diode pair. This structure has potential for applications at submillimeter-wave frequencies where a large amount of LO power is not easily available. >

A planar wideband 80-200 GHz subharmonic receiver

A wideband planar subharmonic mixer has been designed for millimeter-wave operation. The receiver consists of a back-to-back Schottky-diode pair integrated at the base of a wideband log-periodic antenna and placed on a silicon lens. The wideband planar receiver results in state-of-the art-performance at 90 GHz (and 182 GHz) with a double-sideband conversion loss and noise temperature of 6.7 dB (and 8.5 dB) and 1080 K (and 1820 K), respectively. These results are about 3 dB higher than the results for best tuned waveguide subharmonic mixers using planar diodes. The design is well suited for higher frequencies (up to 1 THz) and for the inclusion of biased back-to-back planar diodes to ease the LO power requirements. The planar subharmonic approach results in an inexpensive wideband receiver, and the design can be easily extended to receiver arrays. >

Suppression of common-mode beat noise from optical amplifiers using a balanced receiver

When a coherent (heterodyne or homodyne), single-mixer type optical receiver is combined with an optical preamplifier or in-line amplifier(s), the S/N is deteriorated severely due to the common-mode (signal-ASE and ASE-ASE) beat noise. When a balanced-type coherent receiver is used, the common-mode beat noise can be suppressed and the ideal, so-called LO-ASE bet-noise-limited, S/N is attainable. The Letter presents a clear experimental demonstration of the suppression of common-mode beat noise by a balanced receiver. The minimum required LO power is determined by the thermal noise or the common-mode rejection ratio (CMRR) of the balanced receiver.