| 1. |
- Hörberg, Mikael, 1972, et al.
(författare)
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A W-band, 92-114 GHz, real-time spectral efficient radio link demonstrating 10 Gbps peak rate in field trial
- 2022
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Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. ; 2022-June, s. 545-548
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Konferensbidrag (refereegranskat)abstract
- This paper reports on a real-time radio-link at W-band (92-114 GHz). 10 Gbps peak rate is reached for a 2000 MHz carrier bandwidth, and 5.7 Gbps is demonstrated over a link-hop of 1.5 km for a 1500 MHz-carrier, running at 128 QAM and 32 QAM, respectively. High integrated radio front-end SIP modules using GaAs technology, achieves a linear TX channel power of +8 dBm, and RX NF of 8 dB from the radio. It is configured to achieve 5.7 Gbps in a radio link with 149 dB system gain.
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| 2. |
- Chen, Jingjing, 1982, et al.
(författare)
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Does LO Noise Floor Limit Performance in Multi-Gigabit Millimeter-Wave Communication?
- 2017
-
Ingår i: IEEE Microwave and Wireless Components Letters. - 1558-1764 .- 1531-1309. ; 27:8, s. 769-771
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Tidskriftsartikel (refereegranskat)abstract
- Extremely high data rate communication can potentially be achieved by combining high-order modulations and wide bandwidths at millimeter-wave (mm-wave) frequencies. However, it has been challenging to practically implement this combination, even if the SNR of the system appears to be sufficiently high. An explanation from a recent theoretical study is that the practical data rates in mm-wave systems are limited by the local oscillator (LO) white phase noise. In this letter, we present an experimental investigation on whether the white noise floor of frequency multiplied LO sources is a major noise contribution to wideband signals. Hardware measurements are performed using multi-gigabit 64 quadrature amplitude modulation (QAM) signals. The measured results show that the transmitter performance degrades as the LO noise floor increases. Hence, the LO noise floor is identified to be one primary limitation for achieving the highest possible data rate in wideband mm-wave systems.
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| 3. |
- Hörberg, Mikael, 1972, et al.
(författare)
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A GaN HEMT X-band cavity oscillator with electronic gain control
- 2016
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Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781509006984 ; 2016-August, s. Art. no. 7540030-
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Konferensbidrag (refereegranskat)abstract
- This paper reports on a very low phase-noise GaN HEMT cavity oscillator at 8.5 GHz based on a reflection amplifier with electronic gain control. The gain control functionality is essential in order to control the open loop gain, which is critical for the phase noise performance. A large loop gain forces the oscillator in deep compression, resulting in increased noise conversion and degraded phase noise. On the other hand, a sufficient gain margin is mandatory to ensure satisfaction of the oscillation condition with margin that covers temperature drift and individual spread. The electronic gain control uses varactors to change the output termination of a reflection amplifier. In this way the loop gain can be set independently of the bias point of the active device and the position of the metal cavity. A minimum phase noise of -136 dBc/Hz@ 100 kHz off-set is achieved, which is comparable to what is reached for a mechanically tuned oscillator in the same process.
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| 4. |
- Hörberg, Mikael, 1972, et al.
(författare)
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An X-band varactor-tuned cavity oscillator
- 2017
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Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781509063604 ; , s. 1938-1941
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Konferensbidrag (refereegranskat)abstract
- This paper reports on an X-band varactor-tuned cavity oscillator. The varactors are mounted on a low loss printed circuit board (PCB) that is intruded inside the cavity, which enables efficient coupling to the RF-field. The varactors' positions are changed by adjusting the intrusion depth of the PCB as well as the horizontal positions of the varactors on the PCB. This compromises between the tuning range and the resonator Q-factor. The active part, i.e., the reflection amplifier, is implemented in GaN-HEMT MMIC technology. A microstrip line couples the cavity to the reflection amplifier. The coupling factor can be controlled by mechanically adjusting the cavity's position. A lateral displacement changes the amplitude coupling, while a displacement along the microstrip line changes the phase condition. A tuning range of 1.6 % about 10 GHz is reached with the PCB placed at 1 mm depth from the cavity wall. The measured phase noise at 100 kHz and 1 MHz offset, respectively, ranges from -111 dBc/Hz to -118 dBc/Hz, and -138 dBc/Hz to -146 dBc/Hz over the tuning range. Increased tuning range can be reached if the varactors are placed deeper into the cavity, but then the phase noise degrades due to the increased tuning sensitivity that causes modulation noise and degradation of large-signal quality factor as the varactors are exposed to a stronger RF-field.
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| 5. |
- Hörberg, Mikael, 1972, et al.
(författare)
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Analysis of a MEMS Tuned Cavity Oscillator on X-Band
- 2017
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 65:9, s. 3257-3268
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports on the analysis of a radio frequency microelectromechanical systems (RF-MEMS) tuned cavity oscillator on X-band based on a GaN-HEMT monolithic microwave integrated circuit reflection amplifier. The RF-MEMS-switches are mounted on a low-loss printed circuit board (PCB) intruded in an aluminum cavity that is coupled to a microstrip line connected to the reflection amplifier. This paper investigates the influence of the number of switches as well as their positions with respect to phase noise and tuning range. Vertical and horizontal positions of the switches are varied with target on optimum trade-off between phase noise and total tuning range. For a three-row MEMS-configuration at 1-mm depth from the end cavity wall, a tuning range of 4.9% is measured. The center frequencies are ranging from 9.84 to 10.33 GHz with measured phase noise of -140 to -129 dBc/Hz at 100-kHz offset. A similar three-row MEMS setup at 2.5-mm depth provides a tuning range of 12.3% with measured phase noise of -133 to -123 dBc/Hz at 100-kHz offset.
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| 6. |
- Hörberg, Mikael, 1972
(författare)
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Low Phase Noise GaN HEMT Oscillator Design based on High-Q resonators
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The thesis considers the design and optimization of oscillators targeting low phase noise, given boundary conditions from the technology. Crucial technology figures are power capability, RF noise figure, low-frequency noise and the quality factor (Q-factor) of the resonator. Parameters that can be optimized from a design perspective are the resonator coupling, bias point and waveforms. The technology used in this study is GaN-HEMT, due to its low RF noise figure, high power capability and good DC to RF efficiency.The focus has been on the resonator coupling which is an essential part of the oscillator design. Strong coupling with high power transfer to the resonator improves the phase noise. Contradictory it will also decrease the loaded Q-factor of the resonator. The optimum coupling factor is found to be between ß=1/2 and ß=1, defined as the ratio of power dissipated in the resonator compared to the total power delivered by the active device.Several designs in various resonator technologies have been investigated. For example, an oscillator based on an aluminum cavity connected to a GaN-MMIC reflection amplifier has a phase noise of -145 dBc/Hz at 100 kHz offset from a 9.9 GHz carrier. The analysis of the coupling’s effect to the cavity shows the optimum phase noise occurs for ß close to unity, which is equivalent to an open loop gain close to 0 dB. A MMIC oscillator based on the same reflection amplifier and a quasi-lumped on-chip-resonator has a phase noise of -106 dBc/Hz at 100 kHz offset from a 15 GHz carrier, which clearly shows that the phase noise scales with the Q-factor of the resonator.A reflection amplifier with an electronically controlled gain is also designed for control of the resonator coupling. Varactors in the termination network perform a gain adjustment without changing the bias point of the active transistor. The phase noise of a cavity oscillator based on this reflection amplifier is -136 dBc/Hz at 100 kHz offset from 8.5 GHz. A similar oscillator with a mechanically tuned cavity has about 3 dB better phase noise. Despite a small degradation in phase noise, the simplicity facilitated with electronic tuning motivates this design for practical applications.High-Q tunable elements are key components for frequency control. This work reports an ohmic cantilever radio frequency electromechanical system (RF-MEMS) integrated on a PCB forming a tunable ground plane inside a cavity. Vertical and horizontal positions of the MEMSs are investigated for trade-offs between tuning-range, frequency resolution and phase noise. Placing the PCB at 1 mm depth from the cavity wall, 5 % tunability around 10 GHz is reached, with 100 kHz phase noise ranging from -140 dBc/Hz to -129 dBc/Hz. Placing the PCB deeper into the cavity, at 2.5 mm, the tuning range can be increased to 12.3 %, with 100 kHz phase noise varying from -133 dBc/Hz to -123 dBc/Hz. A varactor-tuned cavity oscillator has been implemented using the same PCB. It presents a tuning range of 1.6 %. The optimum phase noise at 100 kHz is ranging from -111 dBc/Hz to -118 dBc/Hz. At 1 MHz offset the phase noise is varying from -138 dBc to -146 dBc/Hz, versus the tuning-range.GaN-HEMT devices from different commercial vendors have been used for the designs. For modeling purposes, low-frequency noise is measured for all devices. A special high-voltage and current low-frequency noise test setup was developed and used for benchmarking of different GaN HEMTs versus other technologies, e.g., GaAs InGaP HBTs and GaAs-HEMTs.
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| 7. |
- Hörberg, Mikael, 1972, et al.
(författare)
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Low phase noise power-efficient MMIC GaN-HEMT Oscillator at 15 GHz based on a Quasi-lumped on-chip resonator
- 2015
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Ingår i: 2015 IEEE MTT-S International Microwave Symposium, IMS 2015. - 9781479982752
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Konferensbidrag (refereegranskat)abstract
- This paper reports on a negative resistance 15 GHz GaN HEMT oscillator using a quasi-lumped integrated resonator. The resonator is based on a lumped element parallel LC resonator and a piece of transmission line acting as impedance transformer and phase compensation. The main advantage of this type of resonator is that it gives good flexibility in choice of impedance level so that it is easy to control the coupling factor between the active device and the resonator which is mandatory to reach good phase noise. An excellent phase noise of -106 dBc/Hz@100 kHz from a 15 GHz carrier is experimentally demonstrated. The oscillator is also very power efficient with a power normalized figure of merit (FOM) of 191 dB, extracted at 100 kHz offset. To the authors' best knowledge this is the highest FOM reported for a GaN HEMT MMIC oscillator.
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| 8. |
- Hörberg, Mikael, 1972
(författare)
-
Optimum GaN HEMT Oscillator Design Targeting Low Phase Noise
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The thesis considers design of low phase noise oscillators, given the boundary condition of the used technology. Important conditions are the power handling of the active device, device noise floor, the quality factor of the resonator, bias settings, and low frequency noise. A particular focus in this study is optimization of the coupling factor between the resonator and the active device, which is the factor that is most easy to influence for a circuit designer. Resonators have to be well matched to the active device to ensure a good performance. As a measure on oscillator design efficiency, the thesis uses an effective noise figure that is compensated for the unloaded quality factor (Q0) of the resonator and the power consumption of the active device.The active device technology in this study is a 0.25 um GaN-HEMT process. All designs are based on a device with 400 um gate periphery that is processed either as a single-dieHEMT assembled in a hybrid solution discrete on PCB, or in a MMIC-implementation with the amplifying part, or the complete oscillator on chip. Low-frequency-noise (LFN)measurements are performed and benchmarked versus other GaN HEMT devices as well as InGaP HBT and GaAs HEMT. It is found that the used device presents relatively low noise in comparison to other GaN HEMTs. It is also found that power-normalized far carrier noise, e.g., @100 kHz is comparable to levels in InGaP HBT devices. Three oscillators, based on similar reflection amplifiers but different resonators, aredesigned. The three resonators are: an external discrete LC-resonator with Q0≈49, a quasilumped on-chip MMIC resonator, Q0≈40, and an external metal cavity, Q0≈3800. For eachresonator, the impedance level is chosen to match the active device. The fabricated oscillator test beds are made flexible so that the small-signal open loop gain can beexperimentally tuned. It is demonstrated that the best phase noise is reached for a smallsignal open-loop gain close to unity. A too high gain margin is normally bad from a phase noise perspective. The discrete hybrid oscillator presents a phase noise of -123 dBc/Hz@100 kHz from a 1 GHz oscillation frequency; the MMIC oscillator presents a phase noise of -106 dBc/Hz@100 kHz from a 15 GHz oscillation frequency; and the cavity based oscillator presents an excellent phase noise of -145 dBc/Hz@100 kHzfrom a 10 GHz oscillation frequency. Normalizing these results versus Q0 and DC-power, results in effective noise figures of 16-22 dB. The effective noise figure is identified to originate primarily in finite DC to RF power efficiency and up-converted flicker noise.
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| 9. |
- Hörberg, Mikael, 1972, et al.
(författare)
-
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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| 10. |
- 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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