| 1. |
- Drakinskiy, Vladimir, 1977, et al.
(författare)
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Development of planar schottky diodes
- 2011
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Ingår i: 22nd International Symposium on Space Terahertz Technology 2011, ISSTT 2011; Tucson, AZ; United States; 25 April 2011 through 28 April 2011. ; , s. 64-
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Konferensbidrag (refereegranskat)abstract
- We present the development of an air-bridged planar Schottky diode process at Chalmers University of Technology for use in submillimeter wave mixer and multiplier circuits. As a first step evaluation has been targeted for heterodyne receivers (atmosphere sounders) operation at 340 GHz. The aim is to develop a reliable and repeatable discrete Schottky diode process, with good electrical and mechanical characteristics, which also can be scaled to smaller anodes and extended to integrated diode circuits for THz frequencies. Air-bridged Schottky structures were demonstrated in the late 1980's as a reliable, high quality alternative to whisker contacted diodes. This approach gives a mechanically stable structure and still low parasitic capacitances. The Chalmers diode process is based on electron beam lithography, with a beam spot less than 5 nm, which allows for precise anode and airdridge formation. Hence, this process module can also be utilized for submicron size anodes and. terahertz monolithic integrated circuits (TMICs). Several batches with different shapes of anodes have been fabricated and evaluated with respect to DC/RF-performance. Repeatability of the diode's characteristics indicates good control of the diode fabrication process. We will present the main fabrication route, optimization and repeatability of the diodes as well as RF results from mixer and multiplier measurements up to 340 GHz.
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| 2. |
- Drakinskiy, Vladimir, 1977, et al.
(författare)
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Development of planar THz Schottky diodes
- 2011
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Ingår i: 6th ESA Workshop on Millimetre-Wave Technology and Applications.
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Konferensbidrag (refereegranskat)abstract
- We present the technological development of the air bridge planar Schottky diode process at Chalmers University of Technology for the use as submillimeter wave mixer and multiplier. Our first evaluation is targeted for the heterodyne receivers (i.e. atmosphere sounders) operation at 340 GHz. The aim is to develop a reliable and repeatable Schottky diode process, with good electrical and mechanical characteristics. In addition, the scalability of the diode geometry for diode integration in THz circuits is also taken into account in this development.
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| 3. |
- Khanal, S, et al.
(författare)
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Thermal Characterization of THz Schottky Diodes Using Transient Current Measurements
- 2014
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Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 4:2, s. 267-276
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a new method for thermal characterization of THz Schottky diodes. The method is based on the transient current behavior, and it enables the extraction of thermal resistances, thermal time-constants, and peak junction temperatures of THz Schottky diodes. Many typical challenges in thermal characterization of small-area diode devices, particularly those related to self-heating and electrical transients, are either avoided or mitigated. The method is validated with measurements of commercially available single-anode Schottky varactor diodes. A verification routine is performed to ensure the accuracy of the measurement setup, and the characterization results are compared against an in-house measurement-based method and against simulation results of two commercial 3-D thermal simulators. For example, characterization result for the total thermal resistance of a Schottky diode with an anode area of 9 $muhbox{m}^{2}$ is within 10% of the average value of 4020 K/W when using all four approaches. The new method can be used to measure small diode devices with thermal time constants down to about 300 ns with the measurement setup described in the paper.
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| 4. |
- Malko, Aleksandra, 1984, et al.
(författare)
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Thermal Analysis of III-V HBV Diode Structures on InP, GaAs, Silicon and Diamond Substrates
- 2013
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Ingår i: International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz. - 2162-2027 .- 2162-2035. ; , s. 1-2
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Konferensbidrag (refereegranskat)abstract
- Thermal analysis of In0.53Ga0.47As and GaAs Heterostructure Barrier Varactors diodes on InP, GaAs, silicon and diamond substrates are presented. The physical dimensions of the analysed structures correspond to the dimensions of a high power integrated HBV frequency multipliers for W-band (70 – 110 GHz). It is shown that material transfer to substrates with higher thermal conductivity will reduce thermal resistance by 21 % and approximately 50 % for In0.53Ga0.47As and GaAs HBVs, respectively. Thus, an enhanced thermal handling capability of the HBV multiplier sources can be obtained.
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| 5. |
- Neumaier, Philipp, 1984, et al.
(författare)
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Molecular Spectroscopy With a Compact 557-GHz Heterodyne Receiver
- 2014
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Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 4:4, s. 469-478
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Tidskriftsartikel (refereegranskat)abstract
- We report on a heterodyne terahertz spectrometer based on a fully integrated 557-GHz receiver and a digital fast Fourier transform spectrometer. The receiver consists of a chain of multipliers and power amplifiers, followed by a heterostructure barrier varactor tripler that subharmonically pumps a membrane GaAs Schottky diode mixer. All sub-components are newly developed and optimized with regard to the overall receiver performance such as noise temperature, power consumption, weight and physical size. The receiver works at room temperature, has a double sideband noise temperature as low as 2000 K at a maximum power consumption of 4.5 W with an Allan time of 10 s and a sideband gain ratio of 0.52. The performance of the spectrometer is demonstrated by absorption spectroscopy of H2O and CH3OH with an instantaneous bandwidth of 1.5 GHz and a resolution of 183 kHz. Several pressure broadening parameters of methanol absorption lines were determined, that agree with other published data. Using the experimentally determined molecular parameters the CH3OH absorption spectrum could be modeled with very high precision.
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| 6. |
- Neumaier, Philipp, 1984, et al.
(författare)
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Molecular spectroscopy with a compact 557 GHz heterodyne receiver
- 2013
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Ingår i: International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz. - 2162-2027 .- 2162-2035.
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Konferensbidrag (refereegranskat)abstract
- In this work the results of spectroscopic and performance measurements with a compact heterodyne receiver in the frequency range between 520 and 590 GHz are presented.
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| 7. |
- Sobis, Peter, 1978, et al.
(författare)
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300 GHz to 1.2 THz GaAs Schottky membrane TMIC’s for next generation space missions
- 2013
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Ingår i: 24th International Symposium on Space Terahertz Technology.
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Konferensbidrag (refereegranskat)abstract
- For future earth observation and planetary exploration missions (e.g. STEAMR, MetOp, GEOSOUNDER, SWI, FIRE, GEOSTAR), high performance room-temperature heterodyne receivers in the 50 GHz to 1.5 THz frequency range are needed. For frequencies up to 300 GHz, GaAs and InP HEMT technology has today become competitive, offering high sensitivity along with all the benefits of traditional MMIC designs, e.g. multifunctional chips and high repeatability. For frequencies let say above 300 GHz, GaAs Schottky diode technology can offer an unprecedented noise performance along with the versatility of working both as a source and detector. The long track record and high reliability of Schottky diode receiver technology makes it the natural choice for high-performance room-temperature space instrumentation operating in the THz range.To fully benefit from the performance that Schottky diode technology can offer, monolithically integrated circuit (MIC) membrane technology [1-3] is necessary. By monolithic integration of THz Schottky diodes on ultrathin substrates and using freestanding metal beam leads, low loss transmission line structures suitable for waveguide integration assembly (waveguide probes, DC and RF interconnects etc.) become possible. Terahertz Membrane Integrated Circuits (TMIC’s) have proven to operate well up to several THz overcoming many of the problems and limitations associated with hybrid technology (using discrete flip chip mounted diodes). Thereto the superior repeatability of TMIC technology opens up for the possibility of multichip integrated assemblies and system on chip solutions, which in turn can enable completely new instrument concepts. We will present on the progress of our GaAs Schottky technology based radiometer systems and the development of monolithically integrated multipliers and mixers based on the Chalmers diode membrane process. Specifically we will present ongoing work from the STEAMR instrument development operating at 340 GHz, as well as on the development of 664/1200 GHz receiver prototypes relevant to upcoming space missions.
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| 8. |
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| 9. |
- Sobis, Peter, 1978, et al.
(författare)
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SWI 1200/600 GHz highly integrated receiver front-ends
- 2015
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Ingår i: 36th ESA Antenna Workshop on Antennas and RF Systems for Space Science, ESA/ESTEC ,Noordwijk, The Netherlands; 6-9 Oct. 2015. ; session S3.1.2
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Konferensbidrag (refereegranskat)
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| 10. |
- Stake, Jan, 1971, et al.
(författare)
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Development of a Compact 557 GHz Heterodyne Receiver
- 2011
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Ingår i: 6th ESA Workshop on Millimetre-Wave Technology and Applications.
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Konferensbidrag (refereegranskat)abstract
- We present the development of a compact 557 GHz receiver front-end, based on a Schottky diode membrane mixer, HBV and mHEMT MMIC LO-technology.
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| 11. |
- Stake, Jan, 1971, et al.
(författare)
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Development of integrated submillimeter wave diodes for sources and detectors
- 2010
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Ingår i: 13th European Microwave Week 2010: Connecting the World, EuMIC 2010; Paris; France; 26 September 2010 through 1 October 2010. - 9782874870156 ; , s. 226-229
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Konferensbidrag (refereegranskat)abstract
- We present progress and status of Heterostructure Barrier Varactor multiplier sources and development of integrated Schottky diode mixers for submillimeter wave applications.
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| 12. |
- Stake, Jan, 1971, et al.
(författare)
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Integrated diode technology for THz applications
- 2013
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Ingår i: SPIE Optics + Photonics, Terahertz Emitters, Receivers, and Applications IV. ; 8846
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Konferensbidrag (refereegranskat)abstract
- This paper provides an overview of research on terahertz integrated diodes and circuits carried out at Chalmers, Göteborg, Sweden. We will present progress on integration techniques for HBV multipliers and Schottky diode mixers and multipliers, including epitaxial transfer of III-Vs and heterogeneous integration on silicon. Moreover, we will present progress on THz device modelling and results from S-parameter characterization of on-chip components at terahertz frequencies. Finally, performance of mixer and multiplier demonstrators based on in-house technology will be presented.
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| 13. |
- Stake, Jan, 1971, et al.
(författare)
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Integrated terahertz electronics for imaging and sensing
- 2012
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Ingår i: 19th International Conference on Microwaves, Radar and Wireless Communications, MIKON 2012, Warsaw, 21-23 May 2012. - 9781457714351 ; 1, s. 122-123
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Konferensbidrag (refereegranskat)abstract
- We present the development of integrated sub millimeter wave receivers and transmitters based on Schottky and HBV-diode technology at Chalmers University of technology
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| 14. |
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| 15. |
- Stake, Jan, 1971, et al.
(författare)
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Terahertz technology and applications
- 2008
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Ingår i: International Symposium on Terahertz between Japan and Sweden.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- THz or submillimetre-wave sensing covers the frequency range from 300 GHz to 10 THz (wavelengths from 1 mm to 30 µm). With energy levels in the 1.2-40 meV range, terahertz interactions with matter involve intermolecular, rather than atomic transitions. This gives rise to some imaging and spectroscopy applications that are unique to this particular region of the electromagnetic spectrum. Many polar molecules in the low pressure gaseous state have strong, narrow band, vibrational and rotational emission or absorption modes that peak in this regime and are used as probes for quantum chemistry, astrophysical processes and the dynamics of planetary atmospheres, including the Earth. Still, the terahertz spectral region is by far the least explored portion of the electromagnetic spectrum. A great obstacle has been the absence of robust and reasonable inexpensive receiver components that can operate at room temperature. The talk will consist of two parts: a) room temperature technology for THz applications and b) terahertz applications in biology and medicine.At Chalmers, several key technologies are explored for future THz systems such as radiometers, radars, spectrometers and communication links for frequencies from approximately 100GHz to several THz. Transistors with 50 nm gate length based on the two dimensional electron gas can at present be used for frequencies up to and above 300 GHz for circuits such as amplifiers, frequency mixers, frequency multipliers, oscillators, and modulators. For even higher frequencies, submicron low noise Schottky diodes are used for heterodyne mixers. We are currently pursuing studies of high functionality THz mixers (SSB) and in-house fabrication of monolithically integrated Schottky diode circuits. Results and progress on single side band mixers at 340 GHz aimed for future climate research satellites such as the ESA PREMIER mission. Furthermore, single chip receivers (MMIC) up to 220 GHz for imaging applications will be presented.THz imaging and spectroscopy for biomedical applications is being targeted for the very first time, including assessment of protein conformational states, molecular binding and interaction, DNA hybridization, isomer identification, skin hydration level, drug delivery, wound healing, tumour identification and margin assessment, and cell processes. The submillimeter wave advanced technology group at Caltech, in conjunction with the group at Chalmers (J.Stake was visiting Caltech under a sabbatical), set up a very flexible exposure and monitoring system to be used to systematically investigate the interaction of THz radiation with cells.The talk will cover the latest results obtained from Chalmers on MMICs and Schottky diode mixers for terahertz frequencies (sensors), as well as results from initial investigations towards thermal and non-thermal effects of THz radiation on biological systems (Caltech/JPL-Chalmers).
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| 16. |
- Stenarson, Jörgen, 1972, et al.
(författare)
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Sensitivity Analysis of TRL Calibration in Waveguide Integrated Membrane Circuits
- 2013
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Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 3:5, s. 558-565
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Tidskriftsartikel (refereegranskat)abstract
- We present a sensitivity analysis on TRL calibrated S-parameter measurements of membrane circuits in the WR-03 waveguide band (220-325 GHz). The impact of waveguide and membrane circuit misalignment, as well as waveguide dimension mismatch is investigated. The analysis is performed for the thru-reflect-line (TRL) calibration applied to E-plane split waveguide blocks carrying membrane circuits. The analysis shows a large influence of the waveguide width tolerance on transmission and reflection phase after the TRL calibration. For a 20 mm long rectangular waveguide with a ± 5 µm width tolerance a phase uncertainty as large as ± 45° for reflection and ± 30° for transmission measurements is observed.
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| 17. |
- Tang, Aik-Yean, 1980, et al.
(författare)
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Analysis of the High Frequency Spreading Resistance for Surface Channel Planar Schottky Diodes
- 2010
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Ingår i: 35th International Conference on Infrared, Millimeter and Terahertz Waves. - 9781424466559 ; :5-10 Sept. 2010, s. 1-2
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Konferensbidrag (refereegranskat)abstract
- Spreading resistance of a planar Schottky diode isstudied as a function of the frequency and buffer layer thickness. The study shows an increase of effective high frequency resistance for a buffer layer thicker than skin depth, due to the parasitic capacitances induced current in buffer layer.
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| 18. |
- Tang, Aik-Yean, 1980, et al.
(författare)
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Analytical Extraction of a Schottky Diode Model from Broadband S-parameters
- 2013
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Ingår i: IEEE transactions on microwave theory and techniques. - 0018-9480 .- 1557-9670. ; 61:5, s. 1870-1878
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Tidskriftsartikel (refereegranskat)abstract
- We present an analytic method to extract Schottky diode parasitic model parameters. All the ten unknown model parameters are extracted via a straightforward step-by-step procedure. The challenges for a proper finger inductance and series resistance extraction are discussed and solutions are recommended. The proposed method is evaluated using three sets of S-parameter data for GaAs-based planar Schottky diodes, i.e., data from measurement up to 110 GHz and 3-D electromagnetic full-wave simulations up to 600 GHz. The extracted models agree well with the measured and simulated data.
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| 19. |
- Tang, Aik-Yean, 1980, et al.
(författare)
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Electro-Thermal Model for Multi-Anode Schottky Diode Multipliers
- 2012
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Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 2:3, s. 290-298
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Tidskriftsartikel (refereegranskat)abstract
- We present a self-consistent electro-thermal model formulti-anode Schottky diode multiplier circuits. The thermal model is developed for an -anode multiplier via a thermal resistance matrix approach. The nonlinear temperature responses of the material are taken into consideration by using a linear temperature dependent approximation for the thermal resistance. The electrothermal model is capable of predicting the hot spot temperature, providing useful information for circuit reliability study as well as high power circuit design and optimization. Examples of the circuit analysis incorporating the electro-thermal model for a substrateless- and a membrane-based multiplier circuits, operating up to 200 GHz, are demonstrated. Compared to simulations without thermal model, the simulations with electro-thermal model agree better with the measurement results. For the substrateless multiplier, the error between the simulated and measured peak output power is reduced from ~13% to ~4% by including the thermal effect.
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| 20. |
- Tang, Aik-Yean, 1980, et al.
(författare)
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Geometry Optimization of THz Sub-harmonic Schottky Mixer Diodes
- 2012
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Ingår i: International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz. - 2162-2027 .- 2162-2035. - 9781467315968 ; , s. 1-2
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Konferensbidrag (refereegranskat)abstract
- We present a systematic analysis of geometry dependent parasitics for THz sub-harmonic Schottky mixer diodes. In particular, the diode RF power coupling bandwidth has been studied, showing a trade-off between the air-bridge finger length and finger separation for operating frequencies beyond 1 THz.
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| 21. |
- Tang, Aik-Yean, 1980, et al.
(författare)
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Impact of Eddy Currents and Crowding Effects on High Frequency Losses in Planar Schottky Diodes
- 2011
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Ingår i: IEEE Transactions on Electron Devices. - 1557-9646 .- 0018-9383. ; 58:10, s. 3260-3269
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present the influence of eddy currents, skin and proximity effects on high-frequency losses in planar terahertz Schottky diodes. The high-frequency losses, particularly losses due to the spreading resistance, are analyzed as a function of the ohmic-contact mesa geometry for frequencies up to 600 GHz. A combination of 3-D electromagnetic (EM) simulations and parameter extraction based on lumped equivalent circuit is used for the analysis. The extracted low-frequency spreading resistance shows a good agreement with the results from electrostatic simulations and experimental data. By taking into consideration the EM field couplings, the analysis shows that the optimum ohmic-contact mesa thickness is approximately one-skin depth at the operating frequency. It is also shown that, for a typical diode, the onset of eddy current loss starts at ∼200 GHz, and the onset of a mixture of skin and proximity effects occurs around ∼400 GHz.
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| 22. |
- Tang, Aik-Yean, 1980, et al.
(författare)
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Modeling of GaAs Schottky diodes for terahertz application
- 2009
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Ingår i: 34th International Conference on Infrared, Millimeter, and Terahertz Waves, Busan, Korea, 2009. - 9781424454167
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Konferensbidrag (refereegranskat)abstract
- 3-D models have been developed to study the series resistance (Rs) at DC and the extrinsic parasitic elements (capacitance and inductance) at high frequencies for a Schottky diode chip. For the Rs study, a comparison with the experimental result has been carried out. High frequency properties and the corresponding S-parameters of the Schottky diode chip are simulated using a 3-D finite element electromagnetic solver. The parasitic elements are then extracted and studied as a function of the diode geometry. The outcome of the studies shows the existence of a significant pad-to-pad capacitance through the semi-insulating substrate which could be improved by implementing tapered shape pads.
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| 23. |
- Tang, Aik-Yean, 1980
(författare)
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Modelling and Characterisation of Terahertz Planar Schottky Diodes
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with the modelling and characterisation of THz planar Schottky diodes, focusing on analyses of geometry-dependent electrical parasitics and the thermal management of the diode chip. Moving towards higher operating frequencies, the diode performance degrades due to high frequency losses, parasitic couplings and self-heating effects.For geometry-dependent electrical parasitics analyses, the diode equivalent circuit parameters can be extracted from the measured or 3-D EM calculated S-parameters. For planar Schottky diodes, the available parameter extraction methods are typically based on an optimisation approach. In this work, a parameter extraction method based on an analytical approach is proposed. The proposed method allows for a fast and more reliable diode model extraction.In this work, the high frequency diode parasitic esistance model is extended to include the eddy current and a mixture of skin and proximity effects.Due to the eddy current and proximity effects, the upper boundary of the buffer layer thickness is approximately one skin depth at the operating frequency, whereas the lower boundary is limited by the spreading resistance at DC.Reactive energies stored in the parasitic capacitances and inductances cause an inherent limitation in the power coupling bandwidth to the intrinsic diode junction. The influence of diode geometry on fundamental power couplingbandwidth limitation is analysed using the Bode-Fano criterion. The result shows a trade-off between the parasitic capacitance and finger inductance,determined by the pad-to-pad distance, in optimising the diode geometry for a wide band diode matching. A systematic thermal analysis of a 200 GHz multiplier chip developed by JPL is performed. The result shows that the chip thermal resistance is in the order of 10^3 K/W, whereas the overall thermal settling time is more than tens of milliseconds. The simulation result is verified through thermal imaging using infrared microscopy. Taking the thermal analysis a step further, a self-consistent electrothermal model for the multiplier chip is proposed. Compared to the circuit analysis without the thermal model, analysis with the electrothermal model shows a better agreement with the measured result, e.g., an error reduction from ~13% to ~4% between the simulated and measured maximum output power, by including the thermal effect.
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| 24. |
- Tang, Aik-Yean, 1980
(författare)
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Modelling of Terahertz Planar Schottky Diodes
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with the modelling of THz planar Schottky diodes, focusing on analyses of the geometry- dependent parasitics and the diode chip thermal management. Moving towards higher operating frequencies, the electromagnetic couplings pose significant limitations on the diode performance.In this work, a model of the loss at high frequencies for planar diodes is developed, specifically the ohmic losses in the cathode buffer mesa is analysed. As a result, the eddy current, skin and proximity effects have been identified as important loss mechanisms in the buffer mesa. This provides an explanation to the strong frequency dependency of the series resistance, which is not explainable using conventional diode series resistance models. Due to the current crowding effect, the upper boundary of the buffer-layer thickness is approximately oneskin depth at the operating frequency, whereas the lower boundary is limited by the spreading resistance at DC.In addition to the ohmic loss, the parasitic capacitance and inductance inherently limit the power coupling to the diode junction. A model is developed to analyse this limitation, i.e by studying the diode resonance requencies as a function of diode geometry. Analysis of the diode resonance frequencies as a function of the pad-to-pad distance is presented. Result shows that there is atrade-off between the parasitic capacitance and inductance, in optimising the power coupling to the junction.Based on the chip layout of frequency doublers developed by Jet Propulsion Laboratory (JPL), a systematic thermal analysis of the multiplier chip is performed. Taking the temperature-dependent material thermal properties intoconsideration, the result shows that the thermal resistance of the 200 GHz multiplier chip is in the order of 10^3 K/W. Meanwhile, the thermal time constant is more than tens of milliseconds. The simulation result is verified through thermal imaging using infrared microscope.Taking the thermal analysis a step further, a self-consistent electro-thermal model for the multiplier chip is proposed. The thermal model is developed using a thermal resistance matrix approach, with a linear-temperature dependency approximation of the thermal resistance. Compared to the circuit analysis without thermal model, analysis with the electro-thermal model shows a better agreement with the measured result, i.e. within 5% of the measured conversion efficiency.
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| 25. |
- Tang, Aik-Yean, 1980, et al.
(författare)
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Parameter Extraction and Geometry Optimisation of Planar Schottky Diodes
- 2010
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Ingår i: 21st International Symposium on Space Terahertz Technology 2010, ISSTT 2010; Oxford; United Kingdom; 23 March 2010 through 25 March 2010. - 9781617823626 ; , s. 361-
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Konferensbidrag (refereegranskat)abstract
- The continuous interests in terahertz (300 GHz to 10 THz) applications have generated technology pressure in the search of reliable, room temperature operational and compact sources and detectors. Various terahertz sources such as optically pumped lasers, backward wave oscillators, and direct multiplied sources have been explored [1]. For direct multiplied sources, the GaAs-based Schottky diode is one of the most critical devices in heterodyne receivers operating at millimetre and sub-millimetre wavelengths. The importance of Schottky diode could be seen from the meticulous efforts in the diode technology advancement. This includes the evolvement of the whisker contact to the surface channel planar diode technology [2] as well as the circuit integration of the discrete Schottky diodes. For high frequency applications, the performance of a GaAs Schottky diode is limited by the parasitic elements [3] and the losses due to skin effects [4]. Thus, systematic studies of the Schottky diode parasitic elements and high frequency losses are very crucial in meeting the design goals. In the search of optimised diode performance, several studies on diode modelling have been performed [5], [6]. In this paper, we present a systematic method to estimate the diode geometry dependent parasitic elements and skin effect losses for diodes operating up to 400 GHz. Different diode geometries, such as padto- pad distance, buffer layer thickness and semi-insulating etch depth have been investigated. The equivalent circuit based method as in [7] has been used, where the parasitic elements are extracted through the least square error fitting of the S-parameters simulated in Ansoft HFSS simulator to the lumped equivalent circuit. Simulations are performed with the semi-insulating substrate of 3 μm (for the case of integrated diode on the membrane) and 10 μm (for the case of discrete diode). In addition, high frequency losses are investigated with the similar method, by using lossy conductors and adding a frequency dependent resistor in the lumped equivalent circuit. Analysis of the simulation and measurement results will be presented.
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