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1.
GaAs-based transistors with the highest f/sub T/ and lowest noise figure reported to date are presented in this letter. A 50-nm T-gate In/sub 0.52/Al/sub 0.48/As/In/sub 0.53/Ga/sub 0.47/As metamorphic high-electron mobility transistors (mHEMTs) on a GaAs substrate show f/sub T/ of 440 GHz, f/sub max/ of 400 GHz, a minimum noise figure of 0.7 dB and an associated gain of 13 dB at 26 GHz, the latter at a drain current of 185 mA/mm and g/sub m/ of 950 mS/mm. In addition, a noise figure of below 1.2 dB with 10.5 dB or higher associated gain at 26 GHz was demonstrated for drain currents in the range 40 to 470 mA/mm at a drain bias of 0.8 V. These devices are ideal for low noise and medium power applications at millimeter-wave frequencies.  相似文献   

2.
This paper describes the design, fabrication, and testing of a novel microstrip superconducting delay line. The structure of the delay line is a double-spiral meander line. The device is patterned from a YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta//(YBCO) thin film deposited on both sides of a 2-in-diameter LaAlO/sub 3/ substrate with a thickness of 0.25 mm. It exhibits low insertion loss up to 20 GHz. At 10 GHz, the measured attenuation is 0.031 dB/ns at 30 K, 0.049 dB/ns at 60 K, and 0.118 dB/ns at 77 K. The magnitudes of the ripples are below 2 dB across the entire band. The total delay at low frequency is approximately 29 ns.  相似文献   

3.
A low insertion-loss single-pole double-throw switch in a standard 0.18-/spl mu/m complementary metal-oxide semiconductor (CMOS) process was developed for 2.4- and 5.8-GHz wireless local area network applications. In order to increase the P/sub 1dB/, the body-floating circuit topology is implemented. A nonlinear CMOS model to predict the switch power performance is also developed. The series-shunt switch achieves a measured P/sub 1dB/ of 21.3 dBm, an insertion loss of 0.7 dB, and an isolation of 35 dB at 2.4 GHz, while at 5.8 GHz, the switch attains a measured P/sub 1dB/ of 20 dBm, an insertion loss of 1.1 dB, and an isolation of 27 dB. The effective chip size is only 0.03 mm/sup 2/. The measured data agree with the simulation results well, including the power-handling capability. To our knowledge, this study presents low insertion loss, high isolation, and good power performance with the smallest chip size among the previously reported 2.4- and 5.8-GHz CMOS switches.  相似文献   

4.
We reported 94-GHz, low conversion loss, and high isolation single balanced active gate mixer based on 70-nm gate length InGaAs/InAlAs metamorphic high-electron mobility transistors (MHEMTs). This mixer showed that the conversion loss and isolation characteristics were 2.5/spl sim/3.5 dB and under -29 dB in the range of 92.95/spl sim/94.5 GHz, respectively. The low conversion loss of the mixer is mainly attributed to the high-performance of the MHEMTs exhibiting a maximum drain current density of 607 mA/mm, an extrinsic transconductance of 1015 mS/mm, a current gain cutoff frequency (f/sub t/) of 330 GHz, and a maximum oscillation frequency (f/sub max/) of 425 GHz. High isolation characteristics are due to hybrid ring coupler which adopted dielectric-supported air-gapped microstrip line structure using surface micromachined technology. To our knowledge, these results are the best performance demonstrated from 94 GHz single balanced mixer utilizing GaAs-based HEMTs in terms of conversion loss as well as isolation characteristics.  相似文献   

5.
Cellular mobile radio operates in full duplex mode, e.g. simultaneously transmits and receives radio frequency signals. A duplexer is constructed with a transmitter final stage filter (T/sub 1/) and a receiver top filter (R/sub 1/). New SAW filters using an extended SAW-resonator-coupled structure have been developed for Japanese cellular radio. A low loss of 1.6 dB for T/sub 1/ and a high rejection level of 50 dB for R/sub 1/ have been achieved.<>  相似文献   

6.
A low-loss and polarisation-insensitive singlemode BaTiO/sub 3/ thin-film waveguide is reported. Polarisation-dependent loss as low as 0.1 dB/cm at a wavelength of 1.55 /spl mu/m has been achieved by a novel Si/sub 3/N/sub 4/ strip-loaded BaTiO/sub 3/ waveguide structure. Propagation loss of less than 0.9 dB/cm for both TE and TM polarisations was measured  相似文献   

7.
采用E-mode 0.25um GaAs pHEMT工艺,2.0mm × 2.0mm 8-pin双侧引脚扁平封装,设计了一款应用于S波段的噪声系数低于0.5dB的低噪声放大器。通过采用共源共栅结构、有源偏置网络和多重反馈网络等技术改进了电路结构,该放大器具有低噪声,高增益,高线性等特点,是手持终端应用上理想的一款低噪声放大器。测试结果表明在2.3-2.7GHz内,增益大于18dB,输入回波损耗小于-10dB,输出回波损耗小于-16dB,输出三阶交调点大于36dB。  相似文献   

8.
DC and microwave measurements on 0.7 mu m single-gate (SG) and dual-gate (DG) In/sub 0.52/Al/sub 0.48/As/In/sub 0.53/Ga/sub 0.47/As planar doped two-dimensional electron gas field-effect transistors (TEGFETs) are reported. The DG devices show a large increase of the g/sub m/ to g/sub D/ ratios, which are as high as 100 at g/sub m/=380 mS/mm, compared with 12 at 420 mS/mm for the single gate (SG) devices on the same chip, as well as 6 dB improvement in the RF power gain compared with their SG counterparts.<>  相似文献   

9.
Continuously variable ferroelectric (BST on sapphire) phase shifters based on all-pass networks are presented. An all-pass network phase shifter consists of only lumped LC elements, and thus the total size of the phase shifter is kept to less than 2.2 mm /spl times/ 2.6 mm at 2.4 GHz. The tunability (C/sub max//C/sub min/) of a BST interdigital capacitor is over 2.9 with a bias voltage of 140 V. The phase shifter provides more than 121/spl deg/ phase shift with the maximum insertion loss of 1.8 dB and the worst case return loss of 12.5 dB from 2.4 GHz to 2.5 GHz. By cascading two identical phase shifters, more than 255/spl deg/ phase shift is obtained with the maximum insertion loss of 3.75 dB. The loss figure-of-merit of both the single- and double-section phase shifters is over 65/spl deg//dB from 2.4 GHz to 2.5 GHz.  相似文献   

10.
The optimisation of X-cut LiNbO/sub 3/ BOA switches for low voltage, low insertion loss operation is described. An LiNbO/sub 3/ waveguide switch operating at 1.3 mu m with an insertion loss of 4.3 dB, switching voltage of 4.7 V and extinction ratio of 21 dB is reported.<>  相似文献   

11.
In this letter, complementary split ring resonators (CSRR) are proposed to design bandpass filters (BPFs) having wide controllable 3-dB fractional bandwidth (FBW). FBW can be varied between 10% and 100%. In addition, filters have the advantages of compactness, sharp rejection, low insertion loss (IL), and low cost. Two prototype fabricated filters of FBW 10.8% and 81.6% show a maximum passband IL of 1.2dB. Filter occupying area is less than 0.25/spl lambda//sub g//spl times/0.15/spl lambda//sub g/, where /spl lambda//sub g/ is the guided wavelength at the midband frequency.  相似文献   

12.
The dc and RF characteristics of Si/SiGe n-MODFETs with buried p-well doping incorporated by ion implantation are reported. At a drain-to-source biasV/sub ds/ of +1 V devices with 140-nm gate length had peak transconductance g/sub m/ of 450 mS/mm, and maximum dc voltage gain A/sub v/ of 20. These devices also had "off-state" drain current I/sub off/ of 0.15 mA/mm at V/sub g/=-0.5 V. Control devices without p-well doping had A/sub v/=8.1 and I/sub off/=13 mA/mm under the same bias conditions. MODFETs with p-well doping had f/sub T/ as high as 72 GHz at V/sub ds/=+1.2 V. These devices also achieved f/sub T/ of 30 GHz at a drain current, I/sub d/, of only 9.8 mA/mm, compared to I/sub d/=30 mA/mm for previously published MODFETs with no p-well doping and similar peak f/sub T/.  相似文献   

13.
This paper presents detailed characterization of a category of edge-suspended coplanar waveguides that were fabricated on low-resistivity silicon substrates using improved CMOS-compatible micromachining techniques. The edge-suspended structure is proposed to provide reduced substrate loss and strong mechanical support at the same time. It is revealed that, at radio or microwave frequencies, the electromagnetic waves are highly concentrated along the edges of the signal line. Removing the silicon underneath the edges of the signal line, along with the silicon between the signal and ground lines, can effectively reduce the substrate coupling and loss. The edge-suspended structure has been implemented by a combination of deep reactive ion etching and anisotropic wet etching. Compared to the conventional silicon-based coplanar waveguides, which show an insertion loss of 2.5dB/mm, the loss of edge-suspended coplanar waveguides with the same dimensions is reduced to as low as 0.5 dB/mm and a much reduced attenuation per wavelength (dB//spl lambda//sub g/) at 39 GHz. Most importantly, the edge-suspended coplanar waveguides feature strong mechanical support provided by the silicon remaining underneath the center of the signal line. The performance of the coplanar waveguides is evaluated by high-frequency measurement and full-wave electromagnetic (EM) simulation. In addition, the resistance, inductance, conductance, capacitance (RLGC) line parameters and the propagation constant of the coplanar waveguides (CPWs) were extracted and analyzed.  相似文献   

14.
AlGaN-GaN high-electron mobility transistors (HEMTs) based on high-resistivity silicon substrate with a 0.17-/spl mu/m T-shape gate length are fabricated. The device exhibits a high drain current density of 550 mA/mm at V/sub GS/=1 V and V/sub DS/=10 V with an intrinsic transconductance (g/sub m/) of 215 mS/mm. A unity current gain cutoff frequency (f/sub t/) of 46 GHz and a maximum oscillation frequency (f/sub max/) of 92 GHz are measured at V/sub DS/=10 V and I/sub DS/=171 mA/mm. The radio-frequency microwave noise performance of the device is obtained at 10 GHz for different drain currents. At V/sub DS/=10 V and I/sub DS/=92 mA/mm, the device exhibits a minimum-noise figure (NF/sub min/) of 1.1 dB and an associated gain (G/sub ass/) of 12 dB. To our knowledge, these results are the best f/sub t/, f/sub max/ and microwave noise performance ever reported on GaN HEMT grown on Silicon substrate.  相似文献   

15.
A low-voltage single power supply enhancement-mode InGaP-AlGaAs-InGaAs pseudomorphic high-electron mobility transistor (PHEMT) is reported for the first time. The fabricated 0.5/spl times/160 /spl mu/m/sup 2/ device shows low knee voltage of 0.3 V, drain-source current (I/sub DS/) of 375 mA/mm and maximum transconductance of 550 mS/mm when drain-source voltage (V/sub DS/) was 2.5 V. High-frequency performance was also achieved; the cut-off frequency(F/sub t/) is 60 GHz and maximum oscillation frequency(F/sub max/) is 128 GHz. The noise figure of the 160-/spl mu/m gate width device at 17 GHz was measured to be 1.02 dB with 10.12 dB associated gain. The E-mode InGaP-AlGaAs-InGaAs PHEMT exhibits a high output power density of 453 mW/mm with a high linear gain of 30.5 dB at 2.4 GHz. The E-mode PHEMT can also achieve a high maximum power added efficiency (PAE) of 70%, when tuned for maximum PAE.  相似文献   

16.
The p-channel operation of a selfaligned heterojunction field-effect transistor (HFET) based on an Si/Si/sub 0.75/Ge/sub 0.25/ heterostructure is demonstrated. Extrinsic transconductance g/sub m/ greater than 8 mS/mm for a device with 1 mu m gate length was measured at 300 K. The high frequency 3 dB point has been measured to be 1.8 GHz.<>  相似文献   

17.
High-performance AlGaN/GaN high electron-mobility transistors with 0.18-/spl mu/m gate length have been fabricated on a sapphire substrate. The devices exhibited an extrinsic transconductance of 212 mS/mm, a unity current gain cutoff frequency (f/sub T/) of 101 GHz, and a maximum oscillation frequency (f/sub MAX/) of 140 GHz. At V/sub ds/=4 V and I/sub ds/=39.4 mA/mm, the devices exhibited a minimum noise figure (NF/sub min/) of 0.48 dB and an associated gain (Ga) of 11.16 dB at 12 GHz. Also, at a fixed drain bias of 4 V with the drain current swept, the lowest NFmin of 0.48 dB at 12 GHz was obtained at I/sub ds/=40 mA/mm, and a peak G/sub a/ of 11.71 dB at 12 GHz was obtained at I/sub ds/=60 mA/mm. With the drain current held at 40 mA/mm and drain bias swept, the NF/sub min/,, increased almost linearly with the increase of drain bias. Meanwhile, the Ga values decreased linearly with the increase of drain bias. At a fixed bias condition (V/sub ds/=4 V and I/sub ds/=40 mA/mm), the NF/sub min/ values at 12 GHz increased from 0.32 dB at -55/spl deg/C to 2.78 dB at 200/spl deg/C. To our knowledge, these data represent the highest f/sub T/ and f/sub MAX/, and the best microwave noise performance of any GaN-based FETs on sapphire substrates ever reported.  相似文献   

18.
Two single-pole, double-throw transmit/receive switches were designed and fabricated with different substrate resistances using a 0.18-/spl mu/m p/sup $/substrate CMOS process. The switch with low substrate resistances exhibits 0.8-dB insertion loss and 17-dBm P/sub 1dB/ at 5.825 GHz, whereas the switch with high substrate resistances has 1-dB insertion loss and 18-dBm P/sub 1dB/. These results suggest that the optimal insertion loss can be achieved with low substrate resistances and 5.8-GHz T/R switches with excellent insertion loss and reasonable power handling capability can be implemented in a 0.18-/spl mu/m CMOS process.  相似文献   

19.
A new method to suppress the cladding-mode coupling loss in fiber Bragg gratings, by independent control of the core refractive index profile and the photosensitive profile, is proposed and experimentally demonstrated. Across the core and the inner cladding, a uniform step photosensitive profile was introduced by co-doping GeO/sub 2/ and B/sub 2/O/sub 3/. The core refractive index was selectively raised by further doping Al/sub 2/O/sub 3/ in the core that has negligible photosensitivity at 244 nm. For strong Bragg gratings inscribed on the fiber, the cladding-mode coupling loss was suppressed below 0.3 dB.  相似文献   

20.
A third-order intermodulation (IM/sub 3/) cancellation technique using a submixer is proposed for a low-power low-distortion mixer. The IM/sub 3/ cancellation is achieved by summing IM/sub 3/ generated in a main mixer and the submixer, which are almost the same amplitude and opposite phase. The mixer was designed to operate at 870 MHz. The proposed technique reduces IM/sub 3/ by 18 dB with a current increase of about 15% and is suitable for low-power applications. The mixer achieved an input-referred third-order intercept point (IIP/sub 3/) of 10 dBm, a gain of 8.7 dB, and an NF of 9.8 dB and dissipates 30 mW from 2.9 V. The IC is fabricated in a SiGe bipolar transistor with f/sub T/= 30 GHz. The IC occupies 1.44 mm/spl times/1.44 mm.  相似文献   

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