Frequency multiplier measurements on heterostructure barriervaractors on a copper substrate

We have fabricated heterostructure barrier varactors (HBV) on a copper substrate, which offers reduced spreading resistance, and improved thermal conductivity compared to an InP substrate. The devices are fabricated without degrading the electrical characteristics. The three-barrier HBV material grown by MOVPE has a leakage current of only 0.1 μA/μm² at 19 V. The maximum capacitance is 0.54 fF/μm². In a frequency tripler experiment a maximum output power of 7.1 mW was generated at 221 GHz with a flange-to-flange efficiency of 7.9%     

Monolithic coplanar transmission lines loaded by heterostructurebarrier varactors for a 60 GHz tripler

Nonlinear transmission lines (NLTLs) loaded by InP-based heterostructure barrier varactors (HBVs) have been fabricated in a monolithic coplanar technology for the first time. The devices were designed for a tripler with a 60 GHz; output frequency. The single HBV diodes, fabricated in a dual barrier scheme, exhibit a capacitance ratio of 6:1, a normalized capacitance of 1.4 fF/μm² and a voltage breakdown in excess of 10 V. Under moderate pumping (20 dBm), a tripling operation with 30% bandwidth was demonstrated with unsaturated conversion efficiency (1%) for a eight-HBV prototype     

Effects of self-heating on planar heterostructure barrier varactordiodes

The conversion efficiency for planar Al_0.7GaAs-GaAs heterostructure barrier varactor triplers is shown to be reduced from a theoretical efficiency of 10% to 3% due to self-heating. The reduction is in accordance with measurements on planar Al_0.7GaAs-GaAs heterostructure barrier varactor (HBV) triplers to 261 GHz at room temperature and with low temperature tripler measurements to 255 GHz. The delivered maximum output power at 261 GHz is 2.0 mW. Future HBV designs should carefully consider and reduce the device thermal resistance and parasitic series resistance. Optimization of the RF circuit for a 10 μm diameter device yielded a delivered output power of 3.6 mW (2.5% conversion efficiency) at 234 GHz     

Optimization of a 250-GHz Schottky tripler using novel fabricationand design techniques

A technique for optimizing a diode waveguide mount for millimeter- and submillimeter-wave applications has been developed. The structure consists of a planar rectangular radiator for which an accurate derivation of impedance is available. The planar radiating probe incorporates the diode contacting tip, is fabricated integrally with the microstrip filter, and is used in a 230-290-GHz frequency tripler. Modification of the tripler using the described technique resulted in an improvement of ≈6 dB in available output power, compared to the authors' previous results for this device. Device output power exceeds 8.5 mW at 245 GHz for an input power of 132 mW. The best flange-to-flange efficiency (in excess of 11%) was achieved at 3.3-mW output power. This technique was then applied to a waveguide mount, incorporating two diodes contacted in parallel, so that greater input power could be handled. This resulted in a tripler with a maximum output power of 15 mW at 270 GHz for an input of 280 mW     

Millimeter Wavelength Frequency Multipliers

Mechanically tuneable millimeter wavelength frequency doublers typically exhibiting 10-percent conversion efficiency at any output frequency in the range 100-260 GHz have been fabricated. Output power varies from 10 mW at 100 GHz to 6 mW at 260 GHz, with a fixed tuned instantaneous 1-dB bandwidth typically 5 percent of the center frequency. A frequency tripler to 215-GHz output frequency is also described. For this device, a mechanically tuneable 3-dB bandwidth of 210 to 240 GHz was obtained, with a peak conversion efficiency of 6 percent at 4.8-mW output power.     

210270GHz短毫米波3倍频器

本文描述了频率复盖210270GHz的3倍频器,最高的倍频效率为5.8%,最大的输出功率发生在输入功率为3050mW的范围内。3倍频器是由基波输入波导WR-12、输出波导WR-4和两波导之间的同轴低通滤波器组成。     

A 270-GHz Tuner-Less Heterostructure Barrier Varactor Frequency Tripler

A tuner-less heterostructure barrier varactor (HBV) frequency tripler has been designed, fabricated, and tested. A conversion efficiency of 7.2% and output power of 6.5 mW were measured at 270 GHz with 90 mW of input power. The performance of this tuner-less HBV tripler is comparable with other HBV frequency multipliers reported in the literature that utilize mechanical tuners to optimize their performance     

Low-parasitic, planar Schottky diodes for millimeter-waveintegrated circuits

The design and fabrication of air-bridged, ultra-low-capacitance Schottky barrier diodes are described. Mott diodes, for mixer applications, and varactor diodes, for use in frequency multipliers, have been produced simultaneously on epitaxial wafers grown by molecular beam epitaxy. Typical mixer diodes have a nominal anode contact area of 4 μm² and exhibit a total zero-bias capacitance of 4.0-4.5 fF (including a parasitic capacitance of approximately 1.0 fF) and a series resistance of 6-8 Ω. Diode chips have been incorporated in hybrid integrated circuit (MIC) mixers for 33-50 GHz and 75-110 GHz and an MIC frequency tripler for 90-140 GHz. Fully monolithic (MMIC) subharmonically pumped mixers for 75-110 GHz have also been fabricated and tested     

Indium gallium arsenide microwave power transistors

Depletion-mode InGaAs microwave power MISFETs with 1-μm gate lengths and up to 1-mm gate widths have been fabricated using an ion-implanted process. The devices employed a plasma-deposited silicon/silicon dioxide gate insulator. The DC current-voltage (I -V) characteristics and RF power performance at 9.7 GHz are presented. The output power, power-added efficiency, and power gain as a function of input power are reported. An output power of 1.07 W at 9.7 GHz with a corresponding power gain and power-added efficiency of 4.3 dB and 38%, respectively, was obtained. The large-gate-width devices provided over twice the previously reported output power for InGaAs MISFETs at X-band. In addition, the first report of RF output stability of InGaAs MISFETs over 24 h period is also presented. An output power stability within 1.2% over 24 h of continuous operation was achieved. In addition, a drain current drift of 4% over 10⁴ s was obtained     

A Broadband CMOS Frequency Tripler Using a Third-Harmonic Enhanced Technique

A third harmonic enhanced technique is proposed to implement a broadband and low-phase-noise CMOS frequency tripler. It nonlinearly combines a pair of differential fundamental signals to generate deep cuts at the peaks of the fundamental waveform, resulting in a strong third harmonic frequency output. This mechanism has inherent suppression on the fundamental and the other harmonics so that only a low-Q high-pass filter on the lossy silicon substrate is applied at the output to further reject the fundamental and the second harmonic frequencies, in contrast to the high-Q filters used in most of the previous tripler designs. The fabricated circuit using 0.18 m CMOS technology is compact and has an input frequency range from 1.7 GHz to 2.25 GHz, or an output frequency range from 5.1 GHz to 6.75 GHz, resulting in about 28% frequency bandwidth. The optimum conversion loss from the tripler is 5.6 dB (27.5% efficiency) at an input power of 2 dBm. The suppressions for the fundamental, second and fourth harmonics in the measurement are better than 11 dB, 9 dB, and 20 dB within an input power range from 2 dBm to 7 dBm.     

A 50 to 70 GHz Power Amplifier Using 90 nm CMOS Technology

A 50 to 70 GHz wideband power amplifier (PA) is developed in MS/RF 90 nm 1P9M CMOS process. This PA achieves a measured P_sat of 13.8 dBm, P_{1 dB} of 10.3 dBm, power added efficiency (PAE) of 12.6%, and linear power gain of 30 dB at 60 GHz under V_DD biased at 1.8 V. When V_DD is biased at 3 V, it exhibits P_sat of 18 dBm, P_{1 dB} of 12 dBm, PAE of 15%, and linear gain of 32.4 dB at 60 GHz. The MMIC PA also has a wide 3 dB bandwidth from 50 to 70 GHz, with a chip size of 0.66 times 0.5 mm². To the author's knowledge, this PA demonstrates the highest output power, with the highest gain among the reported CMOS PAs in V-band.     

Planar multibarrier 80/240-GHz heterostructure barrier varactortriplers

Prototype planar four barrier GaAs/Al_0.7Ga_0.3As heterostructure barrier varactors (HBV's) for frequency tripling from 80 to 240 GHz have been fabricated using a process in which the device surface channel is etched prior to the formation of the contact pad-to-anode air-bridge finger. Formation of the device air-bridge finger after etching the surface channel is facilitated by a trench planarization technique and yields a device with minimal parasitic capacitances. Planar four-barrier HBV triplers with nominal 10-μm diameter anodes have been tested in a crossed-waveguide tripler block; as much as 2 mW of power has been generated at 252 GHz with a flange to-flange tripling efficiency of 25%. These devices are the first planar or multibarrier HBV triplers reported and their output powers are nearly double that of previous whisker-contacted single-barrier HBVs     

Short channel AlGaN/GaN MODFET's with 50-GHz fT and1.7-W/mm output-power at 10 GHz

A thin barrier-donor layer of 200 Å was used to increase the active input capacitance and improve the extrinsic current-gain cutoff frequency (f_t) of short-gate-length AlGaN/GaN MODFETs. 0.2-μm gate-length devices fabricated on such an epi-structure with sheet carrier density of ~8×10¹² cm^-2 and mobility of 1200 cm²/Vs showed a record f_t of 50 GHz for GaN based FETs. High channel saturation current and transconductance of 800 mA/mm and 240 mS/mm respectively were also achieved along with breakdown voltages of 80 V per μm gate-drain spacing. These excellent characteristics translated into a CW output power density of 1.7 W/mm at 10 GHz, exceeding previous record for a solid-state HEMT     

A Novel Quasi-Optical Frequency Multiplier Design for Millimeter and Submillimeter Wavelengths

This paper describes a novel design for millimeter and sub-millimeter wavelength varactor frequency triplers and quadruplers. The varactor diode is coupled to the pump source via waveguide and stripline impedance matching and filtering structures. Output power at the various harmonics of the pump frequency is fed to quasi-optical filtering and tuning elements. The low-loss quasi-optical structures enable near-optimum control of the impedances seen by the varactor diode at the idler and output frequencies, resulting in efficient high-order harmonic conversion. A minimum efficiency of 4 percent with 30-mW input power has been obtained for a tripler operating between 200 and 280 GHz, with a peak efficiency of 8 percent between 250 and 280 GHz. Another tripler, designed for the 260-350-GHz band, gave a minimum conversion efficiency of 3 percent with 30-mW input power, with a peak efficiency of 5 percent at 340 GHz.     

Power-impedance-frequency limitations of IMPATT oscillators calculated from a scaling approximation

The obtainable CW power of silicon IMPATT oscillators, as a function of frequency, is calculated by scaling from reference results. The analysis differs from previous treatments in that the microwave circuit impedance limitation, as observed experimentally, is utilized simultaneously with thermal impedance limitations to uniquely determine device diameter, operating currents, and output power. Results are presented for single and multiple (parallel) units on copper and diamond mounting studs, and for both single (p⁺-n-n⁺) and double-drift-region (p⁺-p-n-n⁺) structures. Obtainable power falls off essentially as 1/f until an ultimate (nonthermal) space-charge-limited current density is reached. Beyond this point the obtainable power varies as f^-2.14. The calculated results on single-drift-region structures are in agreement with experimental observations over the range of frequencies from 13 to 55 GHz, and the analysis predicts an obtainable power of 300 mW at 110 GHz for a double-drift-region structure with 10 percent conversion efficiency.     

Ion-implanted high microwave power indium phosphide transistors

Encapsulated rapid thermal annealing (RTA) has been used in the fabrication of indium phosphide (InP) power metal-insulator-semiconductor field-effect transistors (MISFETs) with ion-implanted source, drain, and active channel regions. The MISFETs had a gate length of 1.4 μm. Six to ten gate fingers per device, with individual gate finger widths of 100 or 125 μm, were used to make MISFETs with total gate widths of 0.75, 0.8, or 1 mm. The source and drain contact regions and the channel region of the MISFETs were fabricated using silicon implants in semi-insulating InP at energies from 60 to 360 keV with doses from 1×10¹² to 5.6×10¹⁴ cm^-2. The implants were activated using RTA at 700°C for 30 s in N₂ or H₂ ambients using a silicon nitride encapsulant. The high-power, high-efficiency MISFETs were characterized at 9.7 GHz, and the output microwave power density for the RTA conditions used was as high as 2.4 W/mm. For a 1-W input at 9.7 GHz gains up to 3.7 dB were observed, with an associated power-added efficiency of 29%. The output power density was 70% greater than that reported for GaAs MESFETs     

High-power generation in IMPATT devices in the 100-200-GHz range

A silicon double-drift IMPATT diode with high uniform doping levels was simulated. Simulation results show that it is possible for silicon IMPATT diodes to generate extremely high pulsed output power for frequencies above 100 GHz under high current-density operation. The highest output power matched to a 1-Ω load resistance obtained at 150 GHz is 37.7 W with a DC current density of 200 kA/cm², although the calculated power conversion efficiency is low. It is also shown that the low-power conversion efficiency limits the diode's continuous wave power operation     

Dependence of GaAs power MESFET microwave performance on device and material parameters

The results of recent X-band measurements on GaAs Power FET's are described. These devices are fabricated with a simple planar process and at least 1-W output power at 9 GHz with 4-dB gain has been obtained from more than 25 slices having carrier concentrations in the range 5 to 15 × 10¹⁶cm^-3. The highest output powers observed to date are 1.0 W at 11 GHz and 3.6 W at 8 GHz with 4-dB gain. Devices have had up to 46-percent power-added efficiency at 8 GHz. The fabrication process is briefly described and the factors contributing to the high output powers reported here are discussed. Some of these factors are epitaxial carrier concentration near 8 × 10¹⁶cm^-3, good device heatsinking, and low parasitic resistance. The observed dependence of microwave performance on total gate width, gate length, pinchoff voltage, epitaxial doping level, etc., is described.     

Performance of P-type epitaxial silicon millimeter-wave IMPATT diodes

A series of p-type IMPATT diodes (p⁺pn⁺) have been fabricated from epitaxially grown silicon for operation as oscillators at Ka-band frequencies. A maximum CW output power level of 700 mW at 29.6 GHz, a maximum conversion efficiency of 10.9 percent, and a minimum FM noise parameter, M, of 25 dB have been measured on this series of p-type diodes. A diode oscillating in a variable height radial disk cavity was frequency tuned from 27.5 to 40 GHz, covering the entire Ka-band, with a 1.4 dB power variation over the tuning range. The minimum CW output power of this tunable oscillator was 360 mW at 6.5 percent efficiency.     

1 W Ku-band AlGaAs/GaAs power HBT's with 72% peak power-addedefficiency

High power and high-efficiency multi-finger heterojunction bipolar transistors (HBT's) have been successfully realized at Ku-band by using an optimum emitter ballasting resistor and a plated heat sink (PHS) structure. Output power of 1 W with power-added efficiency (PAE) of 72% at 12 GHz has been achieved from a 10-finger HBT with the total emitter size of 300 μm². 72% PAE with the output power density of 5.0 W/mm is the best performance ever reported for solid-state power devices with output powers more than 1 W at Ku-band