| 1. |
- Alfonso, E., et al.
(författare)
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Design of microwave circuits in ridge gap waveguide technology
- 2010
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Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781424460564 ; , s. 1544 - 1547
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Konferensbidrag (refereegranskat)abstract
- This paper presents recent advances is a new waveguiding technology referred to as ridge gap waveguides. The main advantages of the ridge gap waveguides compared to hollow waveguides are that they are planar and much cheaper to manufacture, in particular at high frequencies such as for millimeter and submillimeter waves. In these waveguides there are no mechanical joints across which electric currents must float. The gap waveguides have lower losses than microstrip lines, and they are completely shielded by metal so no additional packaging is needed, in contrast to the severe packaging problems associated with microstrip circuits. The gap waveguides are realized in a narrow gap between two parallel metal plates by using a texture on one of the surfaces. The waves follow metal ridges in the textured surface. All wave propagation in other directions is prohibited (in cutoff) by realizing a high impedance (ideally a perfect magnetic conductor) through the textured surface at both sides of all ridges. Thereby, cavity resonances do not appear within the band of operation. The paper studies the characteristic impedance of the line and presents simulations and measurements of circuits designed using this technology.
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| 2. |
- Alleaume, Pierre Franck, et al.
(författare)
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A highly integrated heterogeneous micro- and mm-wave platform
- 2010
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Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781424477326 ; , s. 461-464
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A highly integrated platform for micro- and mmwave frequency applications is introduced. The platform utilizes heterogeneous process modules with integrated passive and tunable devices together with silicon and GaAs MMIC technology to achieve outstanding flexibility. The different process modules are accounted for and their feasibility is proven through a number of application demonstrators from 23GHz telecom backhauling and 77GHz automotive radar indicating excellent performance. © 2010 IEEE.
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| 3. |
- Andersson, Christer, 1982, et al.
(författare)
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Decade bandwidth high efficiency GaN HEMT power amplifier designed with resistive harmonic loading
- 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 use of resistive loading at higher harmonics in wideband power amplifier design is proposed. Although the theoretical efficiency of such operation is lower than other classes the significantly simplified load network design potentially allows for multi-octave realizations. A decade bandwidth (0.4-4.1 GHz) GaN HEMT power amplifier was thereby designed, delivering more than 40 dBm output power with 10-15 dB gain and 40-62% drain efficiency. Linearized modulated signal amplification was then successfully demonstrated at multiple frequencies (0.9 to 3.5 GHz), using various downlink signals (LTE, WCDMA, WiMAX), with resulting ACLR lower than 46 dBc.
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| 4. |
- ANDERSSON, MICHAEL, 1988, et al.
(författare)
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Noise Figure Characterization of a Subharmonic Graphene FET Mixer
- 2012
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Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781467310871
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Konferensbidrag (refereegranskat)abstract
- We report on the first room temperature noise figure measurement of a graphene FET subharmonic resistive mixer in the interval fRF = 2-5 GHz. Due to an 8 nm thin Al2O3 gate dielectric it can operate with a conversion loss in the range 20-22 dB at only 0 dBm of local oscillator power. The measurement yields a noise figure close to the conversion loss, thus determining the noise to be thermal in origin, which is promising for cryogenic applications. The general route to lower noise figure is an improvement of the conversion loss.
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| 5. |
- Angelov, Iltcho, 1943, et al.
(författare)
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On the large-signal modeling of High Power AlGaN/GaN HEMTs
- 2012
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Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781467310871
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Konferensbidrag (refereegranskat)abstract
- In this paper are given some recent results on modeling of High Power GaN HEMT devices. The GaN HEMT is very promising for high power application, but we push device to the limits, so many issues are becoming critical. For example, access resistances Rs, Rd in high power GAN HEMT are bias and temperature dependent-their extraction from cold FET measurements can lead to over optimistic prediction for output power. Thermal management, self-heating modeling are another very important issue-they influence reliability, power and PAE. Models without dynamic self-heating are not practical for GaN. The models without breakdown can easily predict world records for PAE, output power/mm etc. Some examples are given using vectorial Large Signal Measurements (LSNA/NVNA) to provide useful, global info about device behavior, influence of traps, knee voltage walkout etc.
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| 6. |
- Avolio, G., et al.
(författare)
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A novel technique for the extraction of nonlinear model for microwave transistors under dynamic-bias operation
- 2013
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Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781467361767 ; , s. Art. no. 6697394-
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Konferensbidrag (refereegranskat)abstract
- In this work we describe a novel technique for the extraction of nonlinear model for microwave transistors from nonlinear measurements obtained by simultaneously driving the device under test with low- and high-frequency excitations. Specifically, the large-signal operating point of the device is set by large-signal low-frequency excitations. On top of these a tickle tone at high-frequency is applied. In this way, one can separate the contributions of the IDS current source and the charge sources by a single measurement. The nonlinear model, based on equations available in commercial CAD tools, is extracted for a 0.15 μm GaAs pHEMT. Good agreement is obtained between model predictions and experimental data.
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| 7. |
- Avolio, G., et al.
(författare)
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Waveforms-based large-signal identification of transistor models
- 2012
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Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781467310871
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Konferensbidrag (refereegranskat)abstract
- Measurements of low-and high-frequency vector-calibrated large-signal waveforms are exploited in this work to identify the parameters of a FET nonlinear model. The I DS nonlinear current source and the nonlinear charge sources' parameters are respectively determined from a small set of low-(2 MHz) and high-frequency (8 GHz) load-pull measurements by using a least square numerical optimization. Under low-frequency operation the contribution of the charge sources and any other reactive element can be neglected. In this way the identification of the IDS parameters is more accurate while remarkably speeding up the optimization routine as well. The proposed procedure is quite general and can be applied to different types of active devices. As case study, a 0.25-μm GaAs pHEMT is considered and the extracted model is validated under conditions different than the ones exploited within the identification step. A very good agreement between model predictions and experimental data is achieved.
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| 8. |
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| 9. |
- Bao, M., et al.
(författare)
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A 31~61 GHz linear transconductance up-conversion mixer with 15 GHz IF-bandwidth
- 2013
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Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X.
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Konferensbidrag (refereegranskat)abstract
- A novel 31-61 GHz up-conversion transconductance mixer is proposed, designed and manufactured in a 0.25 μm InP DHBT technology, which consists of a main and an auxiliary mixer. At large input power, the conversion gain compression of the main mixer is compensated by the gain expansion of the auxiliary mixer; consequently, the linearity of the combined two mixers is improved. The measured output referred 1-dB compression point, OP1dB, is -2.2 dBm to -0.57 dBm in the frequency range, which to the authors' knowledge, is the best obtained among the up-conversion mixers published so far. Moreover, the mixer also demonstrates a broad IF bandwidth of 0~15 GHz, supporting up-conversion of high datarate baseband signals. © 2013 IEEE.
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| 10. |
- Bryllert, Tomas, 1974, et al.
(författare)
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A broadband heterostructure barrier varactor tripler source
- 2010
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Ingår i: 2010 IEEE MTT-S International Microwave Symposium (MTT). - 0149-645X. - 9781424460571 ; , s. 344-347
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Konferensbidrag (refereegranskat)abstract
- We present the first demonstration of a broadband Heterostructure Barrier Varactor tripler, designed to cover a major part of the WR-8 waveguide band. The source comprises a waveguide housing, a six-barrier InP-HBV diode flip-chip mounted on an AlN microstrip filter circuit. The conversion loss 3-dB bandwidth was measured to 17 % at a center frequency of 112 GHz. The maximum output power was more than 15 mW for an input power of 300 mW. There are no mechanical tuners or DC-bias, which simplifies assembly and allows for ultra-compact design.
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