| 1. |
- Abbasi, Morteza, 1982, et al.
(författare)
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A Broadband 60-to-120 GHz single-chip MMIC multiplier chain
- 2009
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Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. ; , s. 441-444
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Konferensbidrag (refereegranskat)abstract
- This paper presents a single-chip 60 GHz to 120 GHz frequency multiplier chain based on 0.1 ?m GaAs mHEMT. The MMIC can deliver 3 to 5 dBm of output power from 110 GHz to 130 GHz with 2 dBm input power and consumes only 65 mW of DC power. The signal at the fundamental frequency is suppressed more than 20 dB over the band of interest. The impedance matching networks are realized using coupled transmission lines.
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| 2. |
- Abbasi, Morteza, 1982, et al.
(författare)
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An E-Band(71-76, 81-86 GHz) Balanced Frequency Tripler for High-Speed Communications
- 2009
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Ingår i: APMC: 2009 ASIA PACIFIC MICROWAVE CONFERENCE. - 9781424428014 ; 1-5, s. 1184-1187
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- An E-Band transistor-based balanced frequency tripler is implemented using a 0.15 mu m GaAs mHEMT process which can be integrated into a single-chip RF front-end. The balanced configuration with 90 degrees hybrids at the input and output improves the port impedance matching which is measured to be better than 15 dB at the input and 10 dB at the output over the frequencies of interest. The tripler has a conversion loss of 11.5 dB from 71 GHz to 76 GHz and 14 dB from 81 GHz to 86 GHz. The second and forth harmonics are suppressed by more than 30 dB and the fundamental frequency by 20 dB. The tripler can deliver -2 dBm output power.
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| 3. |
- Abbasi, Morteza, 1982, et al.
(författare)
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Single-Chip Frequency Multiplier Chains for Millimeter-Wave Signal Generation
- 2009
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 57:12, s. 3134-3142
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Tidskriftsartikel (refereegranskat)abstract
- Two single-chip frequency multiplier chains targeting 118 and 183 GHz output frequencies are presented. The chips are fabricated in a 0.1 mu m GaAs metamorphic high electron-mobility transistor process. The D-band frequency doubler chain covers 110 to 130 GHz with peak output power of 5 dBm. The chip requires 2 dBm input power and consumes only 65 mW of dc power. The signal at the fundamental frequency is suppressed more than 25 dB compared to the desired output signal over the band of interest. The G-band frequency sextupler (x6) chain covers 155 to 195 GHz with 0 dBm peak output power and requires 6.5 dBm input power and 92.5 mW dc power. The input signal to the multiplier chain can be reduced to 4 dBm while the output power drops only by 0.5 dB. The unwanted harmonics are suppressed more than 30 dB compared to the desired signal. An additional 183 GHz power amplifier is presented to be used after the x6 frequency multiplier chain if higher output power is required. The amplifier delivers 5 dBm output power with a small-signal gain of 9 dB from 155 to 195 GHz. The impedance matching networks are realized using coupled transmission lines which is shown to be a scalable and straightforward structure to use in amplifier design. Microstrip transmission lines are used in all the designs.
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| 4. |
- Andersson, Kristoffer, 1976, et al.
(författare)
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Fabrication and characterization of field-plated buried-gate SiC MESFETs
- 2006
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Ingår i: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 27:7, s. 573-575
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Tidskriftsartikel (refereegranskat)abstract
- Silicon carbide (SiC) MESFETs were fabricated using a standard SiC MESFET structure with the application of the "buried-channel" and field-plate (FP) techniques in the process. FPs combined with a buried-gate are shown to be favorable concerning output power density and power-added efficiency (PAE), due to higher breakdown voltage and decreased output conductance. A very high power density of 7.8 W/mm was measured on-wafer at 3 GHz for a two-finger 400-/spl mu/m gate periphery SiC MESFET. The PAE for this device was 70% at class AB bias. Two-tone measurements at 3 GHz /spl plusmn/ 100 kHz indicate an optimum FP length for high linearity operation.
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| 5. |
- Angelov, Iltcho, 1943, et al.
(författare)
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Large-Signal Modelling and Comparison of AlGaN/GaN HEMTs and SiC MESFETs
- 2006
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Ingår i: IEEE Asia PAcific Microwave Conference, 2006, Yokohama, Japan. - 9784902339116 ; , s. 279-282
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Konferensbidrag (refereegranskat)abstract
- The Large Signal (LS) model for GaN and SiC FET devices was developed and evaluated with DC, S, and LS measurements. Special attention was paid to improve the management of harmonics and provide. a more physical treatment of the dispersion. The model was implemented in a commercial CAD tool and exhibit good overall accuracy.
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| 6. |
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| 7. |
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| 8. |
- Cao, Haiying, 1982, et al.
(författare)
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Compensation of Transmitter Distortion Using a Nonlinear Modeling Approach
- 2008
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Ingår i: International Workshop on Integrated Nonlinear Microwave and Millimetre-wave Circuits 2008. - 9781424426461 ; , s. 131-134
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Konferensbidrag (refereegranskat)abstract
- In this paper, a nonlinear modeling approach is used to demonstrate a joint compensation scheme for the linear and nonlinear distortions in the I/Q modulator and the power amplifier. Based on this nonlinear model, a digital pre-compensator is constructed. The effects of these two mostdominant nonlinear components in a modern transmitter cantherefore be digitally pre-compensated in a single step. The results are verified by experiments, and the proposed approach shows promising performance.
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| 9. |
- Cao, Haiying, 1982, et al.
(författare)
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Dual-Input Nonlinear Modeling for I/Q Modulator Distortion Compensation
- 2009
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Ingår i: 2009 IEEE Radio and Wireless Symposium, RWS 2009; San Diego, CA; United States; 18 January 2008 through 22 January 2008. - 9781424426997 ; , s. 39-42
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Konferensbidrag (refereegranskat)abstract
- This paper focuses on modeling and compensation of both linear and nonlinear distortions in RF I/Q modulators using a dual-input Volterra series-based modeling approach. Moreover, dual-input memory polynomial and dual-input dynamic deviation reduction-based Volterra series models are proposed. The proposed models are evaluated by digital pre-compensation of a high performance I/Q modulator with a wideband input signal. The results show that the proposed dual-input models efficiently compensate for distortion in the I/Q modulator and may therefore greatly improve performance in modern communication systems.
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| 10. |
- Cao, Haiying, 1982, et al.
(författare)
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I/Q Imbalance Compensation Using a Nonlinear Modeling Approach
- 2009
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 57:3, s. 513-518
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Tidskriftsartikel (refereegranskat)abstract
- In-phase/quadrature (I/Q) imbalance is one of the main sources of distortion in RF modulators. In this paper, a dual-input nonlinear model based on a real-valued Volterra series is proposed for compensation of the nonlinear frequency-dependent I/Q imbalance. First, different sources of distortion are identified from experimental measurements, then a dual-input nonlinear I/Q imbalance model is developed. Further, the inverse model is used for I/Q imbalance compensation. Finally, the performance of the I/Q imbalance compensator is evaluated with both simulations and experiments. In comparison with previously published results, the proposed I/Q imbalance compensator shows significantly improved performance. Thus, we prove that a complete nonlinear I/Q imbalance compensation can minimize the effects of the RF modulator in high-performance digital communication systems.
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