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Chaturvedi S.,Gallium Arsenide Enabling Technology Center | Bhalke S.,Gallium Arsenide Enabling Technology Center | Arora V.,Solid State Physics Laboratory | Koul S.,Indian Institute of Technology Delhi
European Microwave Week 2010, EuMW2010: Connecting the World, Conference Proceedings - European Microwave Conference, EuMC 2010 | Year: 2010

We report here the results of study of Glob top encapsulation of an MMIC amplifier and a multi-chip system. A broadband (2.5-5.0 GHz) amplifier MMIC and a VCO+ HPA system working in L-Band were packaged using Glob top encapsulant epoxy. The effect of this encapsulation on the performance of these MMICs was characterized. The alteration in performance is analyzed and method to compensate the alteration is suggested. © 2010 EuMA.

Gugulothu R.,Gallium Arsenide Enabling Technology Center | Bhalke S.,Gallium Arsenide Enabling Technology Center | Chaturvedi S.,Gallium Arsenide Enabling Technology Center
IEEE MTT-S International Microwave and RF Conference 2015, IMaRC 2015 | Year: 2015

This paper presents the design of 50ohm microstrip line, modelling of the metal ceramic package, packaging and characterization of a GaAs MMIC die in the metal ceramic package with optimised interconnections and validation of its performance parameters. The packaged MMIC was characterized under various environmental conditions like temperature cycling, burn-in test and life tests at as per MIL-STD 883 standard. The MMIC performance was monitored before and after every test condition. The packaged amplifier MMIC resulted in good input /output return losses (better than 17dB), linear gain of 20dB, gain flatness of less than 0.5dB, P1dB of 12dBm. It has shown very low drift in gain of plus/minus 0.22dB against 1dB and variation of 1percent in Ids against 10percent. © 2015 IEEE.

Chaturvedi S.,Gallium Arsenide Enabling Technology Center | Manuraj M.,Gallium Arsenide Enabling Technology Center | Bhalke S.,Gallium Arsenide Enabling Technology Center | Arora V.,Solid State Physics Laboratory SSPL | And 2 more authors.
IEEE MTT-S International Microwave and RF Conference 2015, IMaRC 2015 | Year: 2015

This paper presents the design and development of a compact C-band down converter realized in a 12mm×12mm surface mount metal ceramic package. The size reduction has been achieved by development of compact sized MMIC components required for the receiver, viz., a double balanced mixer, a voltage controlled oscillator with on-chip varactor and RF and IF amplifiers. All the MMICs have been designed and fabricated using indigenously developed 0.7μm GaAs MESFET (G7A) technology at GAETEC. The receiver works in a frequency range of 5.0-6.0 GHz and produces down converted signal in 500-1500 MHz band when beaten with internal LO of the receiver, operated at 4.5 GHz. The conversion gain of the receiver is 27dB with a noise figure of 5dB. The RF-IF and LO-IF isolation of better than 25dB is achieved though EM optimized placement of MMICs and isolation barriers inside the package. © 2015 IEEE.

Raj M.,Gallium Arsenide Enabling Technology Center | Chaturvedi S.,Gallium Arsenide Enabling Technology Center | Sazid M.,Solid State Physics Laboratory SSPL | Badnikar S.L.,Solid State Physics Laboratory SSPL | Sehgal B.K.,Solid State Physics Laboratory SSPL
IEEE MTT-S International Microwave and RF Conference 2015, IMaRC 2015 | Year: 2015

A broadband FET resistive mixer MMIC on GaAs substrate is described in this paper. A non-linear model of MESFET operating in passive mode (Vds=0V) developed for design and simulation of mixer has also been analyzed. Measured mixer results match closely with the simulations based on the developed model. The on-chip broadband spiral baluns delivered wide frequency range from 230 MHz to 1.8 GHz while the LO/RF frequency coverage was from 2-8 GHz. 10 dB conversion loss was achieved for 500 MHz IF at 5 GHz RF frequency, and 10 dBm LO power. The mixer exhibited >10 dBm input 1dB compression point, 18 dBm input 3rd order intercept point and >30 dB LO-IF and RF-IF isolation. The mixer was realized in compact chip area of 2.8 × 2.6 mm2 through intensive EM simulations using ADS momentum EM simulator and was fabricated using the standard G7A MESFET process at GAETEC. © 2015 IEEE.

Srinivasa Rao N.,Central University of Costa Rica | Pathak A.P.,Central University of Costa Rica | Sathish N.,Central University of Costa Rica | Devaraju G.,Central University of Costa Rica | And 5 more authors.
Solid State Communications | Year: 2010

Ge nanocrystals embedded in an SiO2 matrix were prepared by the atom beam co-sputtering (ABS) method from a composite target of Ge and SiO 2. The as-deposited films were rapid thermally annealed at the temperatures 700 and 800 °C in nitrogen ambience. The structure of the films was evaluated by using X-ray diffraction (XRD) and Raman spectroscopy. XRD results reveal that as-deposited films are amorphous in nature whereas annealed samples show crystalline nature. Raman scattering spectra showed a peak of GeGe vibrational mode shifted downwards to 297 cm-1, presumably caused by quantum confinement of phonons in the Ge nanocrystals. Rutherford backscattering spectrometry has been used to measure the thickness and Ge composition of the composite films. Size variation of Ge nanocrystals with annealing temperature has been discussed. The advantages of ABS over other methods are highlighted. © 2010 Elsevier Ltd. All rights reserved.

Singh S.,Indian Space Research Organization ISRO | Giridhar M.S.,Indian Space Research Organization ISRO | Rao C.V.N.,Indian Space Research Organization ISRO | Bhalke S.,Gallium Arsenide Enabling Technology Center | Islam R.,Indian Space Research Organization ISRO
Journal of Micro/ Nanolithography, MEMS, and MOEMS | Year: 2015

This paper describes the architecture of microstrip (MS) interfaced packaging of a coplanar-waveguide (CPW)-based radio frequency microelectromechanical systems (RF MEMS) switch in a hermetic metalceramic RF package. The switch is integrated along with CPW to MS (CPW-MS) transitions within the package itself. This makes the MS interfaced packaged switch module readily mountable on MS based RF boards and subsystems. The CPW-MS transition for the package was designed as a separate off-chip entity on an alumina substrate and utilizes via hole. The integrated three-dimensional model of the package consisting of the RF MEMS switch and the transitions was simulated using high frequency structure simulator. The realized module shows an insertion loss of 0.2 and 1.1 dB at 100 MHz and 7 GHz, respectively. The measured isolation is better than 60 dB at 100 MHz and 30 dB at 7 GHz. The return loss is better than 15 dB up to 7 GHz. The estimated packaging and transitioning loss is 0.5 dB at 5 GHz. This packaging architecture is a planar solution for the MS interfaced packaging of CPW based RF MEMS switches for designers who do not have access to high-end technologies, such as zero-level packaging, through silicon via or low temperature co-fired ceramics. © Society of Photo-Optical Instrumentation Engineers.

Chaturvedi S.,Gallium Arsenide Enabling Technology Center | Saravanan G.S.,Solid State Physics Laboratory | Bhat K.M.,Solid State Physics Laboratory | Bhalke S.,Gallium Arsenide Enabling Technology Center
2013 IEEE MTT-S International Microwave and RF Conference, IMaRC 2013 | Year: 2013

Design and development of a planar schottky diode which is process compatible with general planar MESFET process is described here. The device geometry has been designed and optimized keeping in view the applications up to Ku-band. The device was fabricated and characterized to extract the diode model. Two representative application circuits, viz. two types of microwave power limiters were designed, fabricated and tested to show the versatility of the device. © 2013 IEEE.

Saravanan G.S.,Gallium Arsenide Enabling Technology Center | Mahadeva B.K.,Solid State Physics Laboratory | Chaturvedi S.,Gallium Arsenide Enabling Technology Center | Mudholkar M.N.,Gallium Arsenide Enabling Technology Center | Muralidharan R.,Gallium Arsenide Enabling Technology Center
2010 International Conference on Compound Semiconductor Manufacturing Technology, CS MANTECH 2010 | Year: 2010

Low contact resistances (Rc) of 0.05-0.07Ω-mm were achieved by rapid thermal alloying of AuGe/Ni/Au ohmic contacts to GaAs MESFETs. 'Under-alloyed' contacts with Rc of 0.12-0.16Ω-mm, immediately after alloying, drifted to very high values of 0.4-0.7Ω-mm at the end of fabrication process ('final Rc'), while optimally alloyed contacts had drifted only to 0.1-0.2Ω-mm. Accelerated thermal aging for optimally alloyed samples at temperatures of 185°C to 230°C showed drifts of the order of 10 - 13% in the 'final' Rc values, which is one of the lowest drifts in MESFETs. Backside SIMS studies revealed the differences in the level and extent of diffusion of alloy materials between the 'under-alloy' and optimum alloy samples. Minimal drifts in contact resistances could be attributed to optimum germanium doping of the active layers, and formation of stable compounds in the metal-semiconductor interface and the access regions.

Chaturvedi S.,Gallium Arsenide Enabling Technology Center | Koul S.K.,Indian Institute of Technology Delhi
Journal of Electronic Packaging, Transactions of the ASME | Year: 2013

Design, fabrication, and test results of a novel 3-layer RF package using a commonly available high frequency laminate are presented in this paper. The developed package can be manufactured using standard multilayer printed circuit board (PCB) manufacturing techniques making it cost effective for commercial applications. The package exhibits excellent RF characteristics up to 6GHz. © 2013 by ASME.

Chaturvedi S.,Gallium Arsenide Enabling Technology Center | Bhalke S.V.,Gallium Arsenide Enabling Technology Center | Sai Saravanan G.,Gallium Arsenide Enabling Technology Center | Koul K.,Indian Institute of Technology Delhi
Progress In Electromagnetics Research C | Year: 2010

Packaging of planar MMICs poses a unique challenge at microwave frequencies as the dimensions of the encapsulating cavity are comparable to wavelength at the operational frequencies. In addition, the effect of ground loops (caused by bond wires exposed to ground over extended length due to gaps between interconnects) deteriorates the situation even further in circuits like MMIC switches requiring high isolation between ports. The ground loops cause reflections thereby deteriorating the insertion loss figure of merit. This paper presents optimization of design of a metal ceramic package used for packaging an SPDT MMIC switch working in the frequency range of 5-6 GHz. The microwave performance of the package was simulated using EM simulation with parameters including cavity dimensions, port placement, gaps between interconnect lines, package feed-thrus and MMIC chip pads. Detailed characterization of the bare package and packaged SPDT MMIC done later shows a good match between the simulated and measured performance. The SPDT MMIC performance degradation was arrested by improvement in the package structure and it showed insertion loss of -l.6dB and input/output (I/O) return losses of ~ 16 dB in the new package as compared to the values of -2.1 dB insertion loss and -12 dB I/O return losses in the original package. The port-to-port isolation remained unchanged (~ 40 dB in both cases) as it is governed by the MMIC assembly inside the package rather than the conditions at the I/O interfaces in this kind of large sized packages.

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