| 1. |
- He, Zhongxia Simon, 1984, et al.
(författare)
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A 12 Gbps Analog QPSK baseband receiver based on Injection-locked VCO
- 2015
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Ingår i: IEEE International Microwave Symposium. - 0149-645X. - 9781479982752
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Konferensbidrag (refereegranskat)abstract
- Injection locking based QPSK demodulation have been reported in several publication, however the data rate is less than Gbps. In this paper, the theory of an oscillator injection locks to a wideband modulated signal is studied. Based on the principle study, a proof of concept QPSK coherent baseband receiver is designed and verified. The receiver is able to demodulator QPSK signal with data rate up to at least 12 Gbps, which is limited by the mixer bandwidth. The receiver has a power consumption of 210 mW. It consists of a novel injection-locked VCO (ILVCO) based carrier recovery block, which can be used for even higher data rates if the theoretical condition proposed in this paper is met.
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| 2. |
- Hörberg, Mikael, 1972, et al.
(författare)
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Phase noise analysis of a tuned-input/tuned-output oscillator based on a GaN HEMT device
- 2014
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Ingår i: 44th European Microwave Conference, EuMC 2014 - Held as Part of the 17th European Microwave Week, EuMW 2014; Fiera di RomaRome; Italy; 6 October 2014 through 9 October 2014. - 9782874870354 ; , s. 1118-1121
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Konferensbidrag (refereegranskat)abstract
- This paper reports on an experimental analysis of phase noise in a tuned-input/tuned-output oscillator based on a bare-die GaN HEMT device. To investigate phase noise dependency on resonator coupling factor (β), the circuit is designed with flexibility to modify the resonant tank, in terms of unloaded quality factor (Q0) and impedance level. The reflection coefficient (Γamp) from the reflection amplifier can also be varied. With exception for very high values of Γamp, the circuit is robust to variations in β. It is more important to choose a bias point where the flicker noise is low and the power reasonably high. A minimum phase noise of -150dBc/Hz @ 1MHz off-set from a 1GHz oscillation frequency and a power normalized figure of merit (FOM) of 186 are reached. An interesting analytical result is also presented; power normalized figure of merit, commonly used for benchmark of oscillators is bound by Q0 and can be related to the theoretical noise floor limit.
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| 3. |
- Hörberg, Mikael, 1972, et al.
(författare)
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Phase-Noise Analysis of an X-Band Ultra-Low Phase-Noise GaN HEMT Based Cavity Oscillator
- 2015
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9480 .- 1557-9670. ; 63:8, s. 2619-2629
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports on an ultra-low phase-noise oscillator based on a GaN HEMT monolithic microwave integrated circuit reflection amplifier and an aluminum cavity resonator. It is experimentally investigated how the oscillator's phase noise depends on the cavity coupling factor, phase matching, and bias condition of the reflection amplifier. For the optimum bias and cavity position phase noise of -145 dBc/Hz and -160 dBc/Hz at offsets of 100 and 400 kHz, respectively, from a 9.9-GHz carrier frequency is reached. This is, to the best of the authors' knowledge, a record in reported performance for any oscillator based on a GaN HEMT device. The optimum performance at 400-kHz offset corresponds to a power normalized figure of merit of 227 and compensating for finite efficiency in the reflection amplifier, the achieved result is within 7 dB from the theoretical noise floor, assuming a linear theory.
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| 4. |
- Hörberg, Mikael, 1972, et al.
(författare)
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RF-MEMS Tuned GaN HEMT based Cavity Oscillator for X-band
- 2017
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Ingår i: IEEE Microwave and Wireless Components Letters. - 1558-1764 .- 1531-1309. ; 27:1, s. 46-48
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Tidskriftsartikel (refereegranskat)abstract
- This letter presents a radio frequency micro-electromechanical systems (RF-MEMS) tuned cavity oscillator for X-band. The active part of the oscillator is implemented in GaN-HEMT MMIC technology. The RF-MEMS-switches are realized on a quartz substrate that is surface mounted on a low loss PCB. The PCB is intruded in an aluminum cavity acting as an electrically moveable wall. For a three-row RF-MEMS setup, a tuning range of 5 % around an oscillation frequency of 10 GHz is demonstrated in measurements. The phase noise is as low as -140 dBc/Hz to -129 dBc/Hz at 100 kHz from the carrier, depending on the configuration of the RF-MEMS.
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| 5. |
- Kildal, Per-Simon, 1951, et al.
(författare)
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Direct Coupling as a Residual Error Contribution During OTA Measurements of Wireless Devices in Reverberation Chamber
- 2009
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Ingår i: 2009 IEEE International Symposium on Antennas and Propagation and USNC/URSI National Radio Science Meeting, APSURSI 2009; North Charleston, SC; United States; 1 June 2009 through 5 June 2009. - 1522-3965. - 9781424436477 ; , s. Art. no. 5171903-
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Konferensbidrag (refereegranskat)abstract
- We have presented an improved theory for the uncertainty of measurements in reverberation chamber. The theory is obtained by including the error due to the direct coupling between the antenna under test and the wall-mounted antennas. The theory includes the Rician K-factor that can be estimated from simple formulas, and an empirical mechanical stirring bandwidth Bmech that is adjusted to get good agreement with the measured STDs. However, Bmech is fixed for a given chamber and stirrer configuration. The new theory is able to describe variations of uncertainty with frequency and loading, and it can very well predict the degradation when platform and polarization stirring is not used. The validation of the theory is representative for efficiency measurements, but it will be equivalent for measuring total radiated power and receiver sensitivity.
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| 6. |
- Kuylenstierna, Dan, 1976, et al.
(författare)
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Design of Low Phase-Noise Oscillators and Wideband VCOs in InGaP HBT Technology
- 2012
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9480 .- 1557-9670. ; 60:11, s. 3420-3430
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Tidskriftsartikel (refereegranskat)abstract
- A method for design of low phase-noise balanced-Colpitts (BC) fixed-frequency oscillators (FFOs) and wideband voltage-controlled oscillators (VCOs) is presented. Analytical expressions describe how to design an oscillator for best phase noise, given a limited Q factor and a certain active device. The theory needs only two free parameters: the impedance (Z(c)) level and tapping ratio (n) of the resonator. It is described how to chose Z(C) and n for low phase noise and large tuning range, respectively. The design method is verified with a low phase-noise FFO and a wideband VCO, both designed in InGaP HBT technology. The BC FFO presents a phase noise of -112 dBc/Hz at 100-kHz offset from a 9.2-GHz carrier. The wideband VCO implemented in the same technology presents a minimum phase noise of -106 dBc/Hz at 100-kHz offset from a 9-GHz carrier. Over the frequency range of 8.4-9.7 GHz, the phase noise is better than -102 dBc/Hz and the output power is 7 +/- 0.5 dBm. The wide tuning range, constant output power, and relatively constant and low phase noise are achieved due to double pairs of tuning varactors, one between emitters and one between collectors. To the authors' best knowledge, this type of double-tuned BC VCO topology has not been previously published.
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| 7. |
- Lai, Szhau, 1985, et al.
(författare)
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A 20 GHz Low Phase Noise Signal Source Using VCO and Mixer in InGaP/GaAs HBT
- 2012
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Ingår i: 2012 IEEE Compound Semiconductor Integrated Circuit Symposium, CSICS 2012, La Jolla, CA, 14 - 17 October 2012. - 1550-8781. - 9781467309295 ; , s. Art. no. 6340056-
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Konferensbidrag (refereegranskat)abstract
- This paper presents a low phase noise 20 GHz signal source based on a voltage control oscillator(VCO) and a mixer integrated on a single MMIC. The mixer generates a third harmonic output by mixing the fundamental and the second harmonic signals of the VCO. Using a relatively low frequency VCO has the advantage of better Q factor and thus better phase noise. The MMIC-signal source is designed in a GaAs-InGaP HBT process. The VCO uses balanced Colpitts topology and the mixer is a high conversion-gain single-balanced mixer. The MMIC delivers signals in the frequency range 19.4-21.2 GHz with an excellent phase noise of -100 to -93 dBc/Hz at 100kHz offset frequency. The output power ranges between -8 and -1 dBm.
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| 8. |
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| 9. |
- Lai, Szhau, 1985, et al.
(författare)
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A method to lower VCO phase noise by using HBT darlington pair
- 2012
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Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781467310871
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Konferensbidrag (refereegranskat)abstract
- The paper presents a novel method to enhance tank voltage swing in LC VCOs design using bipolar transistor. The method is successfully demonstrated in an InGaP/GaAs HBT MMIC process. A gm-boosted VCO and a modified version, using Darlington-pair transistors, are compared. The latter exhibits lower phase noise, increased tuning range, and less variation in output power. The gm-boosted VCO has tuning range of 22.8% centered at 5.7GHz and phase noise ranging from 103 to 95 dBc/Hz at offset frequency of 100kHz. The modified version using Darlington pair has tuning range of 26% centered at 5.9 GHz and phase noise ranging from 103.5 to 98.5 dBc/Hz at offset frequency of 100kHz.
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| 10. |
- Lai, Szhau, 1985, et al.
(författare)
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A varactor model including valanche noise source for VCOs phase noise simulation
- 2011
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Ingår i: 41th European Microwave Conference , Manchester, UK, Oct 10-13, 2011. - 9781612842356 ; , s. 591-594
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Konferensbidrag (refereegranskat)abstract
- Abstract — This work studies an important area of oscillatoroperation – VCO biased at varactor breakdown. In this operation, the oscillator’s phase noise is primarily determined by avalanche noise generated in the varactor, i.e., the phase noise can be modulated by the incremental shot noise generated at varactor breakdown. A simple experimental diode model was optimized for modeling varactor-breakdown current and an empirical shot noise model based on Hine’s theory presents good agreement with noise power measurements of varactors.The developed varactor noise-model has successfully been used to simulate the phase noise of a single-ended Colpitts InGaP HBT VCO over and beyond the varactor’s breakdown voltage. The VCO presents a phase noise below -100dBc/Hz for varactor voltages lower than breakdown voltage. Beyond the breakdown the phase noise gradually increases to -60 dBc/Hz@100kHz with a centre frequency deviating less than 0.6% from a 7.38GHz carrier.
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