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- Cha, Eunjung, 1985, et al.
(författare)
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Cryogenic low-noise InP HEMTs: A source-drain distance study
- 2016
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Ingår i: 2016 Compound Semiconductor Week, CSW 2016. - 9781509019649 ; , s. Article number 7528576-
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Konferensbidrag (refereegranskat)abstract
- The scaling effect of the source-drain distance was investigated in order to improve the performance of low-noise InP HEMTs at cryogenic temperatures 4-15 K. The highest dc transconductance at an operating temperature of 4.8 K and low bias power was achieved at a source-drain distance of 1.4 mu m. The extracted HEMT minimum noise temperature was 0.9 K at 5.8 GHz for a 3-stage 4-8 GHz hybrid low-noise amplifier at 10 K.
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| 2. |
- Cha, Eunjung, et al.
(författare)
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Two-Finger InP HEMT Design for Stable Cryogenic Operation of Ultra-Low-Noise Ka-and Q-Band LNAs
- 2017
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Ingår i: IEEE transactions on microwave theory and techniques. - : Institute of Electrical and Electronics Engineers Inc.. - 0018-9480 .- 1557-9670. ; 65:12, s. 5171-5180
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the cryogenic stability of two-finger 100-nm gate-length InP HEMTs aimed for Ka-and Q-band ultra-low noise amplifiers (LNAs). InP HEMTs with unit gate widths ranging between 30 and 50 mu text{m} exhibit unstable cryogenic behavior with jumps in drain current and discontinuous peaks in transconductance. We also find that shorter gate length enhances the cryogenic instability. We demonstrate that the instability of two-finger transistors can be suppressed by either adding a source air bridge, connecting the back end of gates, or increasing the gate resistance. A three-stage 24-40 GHz and a four-stage 28-52-GHz monolithic microwave-integrated circuit LNA using the stabilized InP HEMTs are presented. The Ka-band amplifier achieves a minimum noise temperature of 7 K at 25.6 GHz with an average noise temperature of 10.6 K at an ambient temperature of 5.5 K. The amplifier gain is 29 dB ± 0.6 dB. The Q-band amplifier exhibits minimum noise temperature of 6.7 K at 32.8 GHz with average noise temperature of 10 K at ambient temperature of 5.5 K. The amplifier gain is 34 dB ± 0.8 dB. To our knowledge, the Ka-and Q-band amplifiers demonstrate the lowest noise temperature reported so far for InP cryogenic LNAs. © 1963-2012 IEEE.
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| 3. |
- Cha, Eunjung, 1985, et al.
(författare)
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Two-Finger InP HEMT Design for Stable Cryogenic Operation of Ultra-Low-Noise Ka- and Q-Band LNAs
- 2017
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9480 .- 1557-9670. ; 65:12, s. 5171-5180
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate the cryogenic stability of two-finger 100-nm gate-length InP HEMTs aimed for Ka- and Q-band ultra-low noise amplifiers (LNAs). InP HEMTs with unit gate widths ranging between 30 and 50 mu m exhibit unstable cryogenic behavior with jumps in drain current and discontinuous peaks in transconductance. We also find that shorter gate length enhances the cryogenic instability. We demonstrate that the instability of two-finger transistors can be suppressed by either adding a source air bridge, connecting the back end of gates, or increasing the gate resistance. A three-stage 24-40 GHz and a four-stage 28-52-GHz monolithic microwave-integrated circuit LNA using the stabilized InP HEMTs are presented. The Ka-band amplifier achieves a minimum noise temperature of 7 K at 25.6 GHz with an average noise temperature of 10.6 K at an ambient temperature of 5.5 K. The amplifier gain is 29 dB +/- 0.6 dB. The Q-band amplifier exhibits minimum noise temperature of 6.7 K at 32.8 GHz with average noise temperature of 10 K at ambient temperature of 5.5 K. The amplifier gain is 34 dB +/- 0.8 dB. To our knowledge, the Ka- and Q-band amplifiers demonstrate the lowest noise temperature reported so far for InP cryogenic LNAs.
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| 4. |
- Cha, Eunjung, 1985, et al.
(författare)
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Two-finger InP HEMT design for stable cryogenic operation of ultra-low-noise Ka-band LNAs
- 2017
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Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781509063604 ; , s. 168-171
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Konferensbidrag (refereegranskat)abstract
- We have investigated the cryogenic stability of two-finger InP HEMTs aimed for Ka-band ultra-low noise amplifiers (LNAs). Unlike two-finger transistors with a large gate-width above 2 χ 50 μm, the transistors with a small gate-width exhibit unstable cryogenic behavior. The instability is suppressed by adding a source air-bridge. The stabilizing effect of the air-bridge is demonstrated both on device and circuit level. A three-stage 2440 GHz monolithic microwave integrated circuit (MMIC) LNA using a stabilized 100-nm HEMT technology is presented. The amplifier achieves a record noise temperature of 7 K at 25.6 GHz with an average noise of 10.6 K across the whole band at an ambient temperature of 5.5 K. The amplifier gain is 29 dB ± 0.6 dB exhibiting very stable and repeatable operation. To our knowledge, this amplifier presents the lowest noise temperature reported so far for InP cryogenic LNAs covering the Ka-band.
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| 5. |
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| 6. |
- Goia, Naiara, 1978, et al.
(författare)
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Cryogenic X-Band Low Noise Amplifiers
- 2007
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Ingår i: 4th ESA International Workshop on Tracking, Telemetry & Command Systems for Space Applications.
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Konferensbidrag (refereegranskat)abstract
- This paper describes a number of cryogenic low noise amplifiers with very low noise for the frequency band 8.4-8.5 GHz. The amplifiers have been designed with different inputs: ostandard coaxialowaveguide ocoaxial followed by a high directivity 30 dB microstrip couplerAt 10 K ambient temperature the three-stage partly InP-based amplifiers have a gain of 33.0+/-0.5 dB and a noise temperature of 5 -7K.The InP transistors used in the amplifiers were processed at Chalmers clean room facility in our own proprietary process.
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| 8. |
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| 10. |
- Kärnfelt, Camilla, 1965, et al.
(författare)
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Flip Chip Assembly of a 40-60 GHz GaAs Microstrip Amplifier
- 2004
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Ingår i: Proceedings of 34th European Microwave Conference. ; 1:1, s. 89-92
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper describes the successful flip chip assembly of a broadband GaAs amplifier in microstrip design. The flip chip technology used was thermo compression (TC) flip chip bonding of the MMICs to gold ball bumps bonded on the thin film patterned alumina carrier. Also, we report on the occurrence of parasitic parallel plate (PPL) modes in the assemblies and we propose and investigate a scheme to eliminate the modes which, to the best our knowledge, have not been reported on before.Finally we introduce our own flip chip transition equivalent circuit and we use this model in ADS to compare the simulated results with measurements. It is fair to say that the equivalent circuit models the flip chip transition well. This work was performed in the European MEDEA+ packaging project HIMICRO.
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