| 1. |
- Bagger, Reza, et al.
(författare)
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Broadband LDMOS 40 W and 55 W integrated power amplifiers
- 2017
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Ingår i: 2017 IEEE MTT-S International Microwave Symposium, IMS 2017. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509063604 ; , s. 1950-1952
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Konferensbidrag (refereegranskat)abstract
- The performance of broadband microwave 40 W and 55 W LDMOS integrated power amplifiers is reported. A 30 V LDMOS process with 500 nm gate length was used for the design. Single and dual die packages were evaluated. A dual die package provides flexibility in output power and efficiency depending on combiner topology at the input and output of the circuit. Different saturated power and efficiency are obtained for different classes, Class A, AB and B operation and for different combiners, Wilkinson, quadrature or balun. Moreover, dual die in Doherty configuration provides a compact solution for better back-off efficiency in a symmetrical / asymmetrical topology. The 40 W design demonstrates 24 %, 1 dB fractional bandwidth around 2.1 GHz, and power added efficiency of 48 % at P-1 dB of 50 W. It showed excellent back-off linearity and best in class memory effect over frequency and temperature. The 55 W design has 28 %, 1 dB fractional bandwidth around 2.2 GHz, and power added efficiency of 49 % at P-1 dB equal to 63 W.
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| 2. |
- Baptista, Emanuel, 1993, et al.
(författare)
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Analysis of thermal coupling effects in integrated MIMO transmitters
- 2017
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Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781509063604 ; , s. 75-78
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Konferensbidrag (refereegranskat)abstract
- This paper presents a detailed analysis of thermal coupling and self-heating effects in highly integrated wireless transmitters. A MIMO transmitter prototype consisting of two closely integrated power amplifiers was built and modelled through microwave and thermal characterizations. The thermal behavior was extracted using FEM software and modelled with an equivalent RC network. The PA model was obtained experimentally using a pulsed setup. An RF-thermal simulator was developed and used with the models to predict joint thermal and electrical behavior. Measurements with modulated communication signals were done and compared with the simulator to demonstrate its feasibility for analysis of thermal effects in highly integrated transmitter applications.
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| 3. |
- Caizzone, Stefano, et al.
(författare)
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Direction of arrival estimation performance for compact antenna arrays with adjustable size
- 2017
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Ingår i: 2017 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM (IMS). - Piscataway : IEEE. - 9781509063604 ; , s. 666-669
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Konferensbidrag (refereegranskat)abstract
- The quest for compact antenna arrays able to perform robust beamforming and high resolution direction of arrival (DOA) estimation is pushing the antenna array dimensions to progressively shrink, with effects in terms of reduced performance not only for the antenna but also for beamforming and DOA estimation algorithms, for which their assumptions about the antenna properties do not hold anymore. This work shows the design and development of an antenna array with adjustable mutual distance between the single elements: such setup will allow to scientifically analyse the effects that progressive miniaturization, i.e. progressively smaller mutual distances between the antennas, have on the DOA estimation algorithms, as well as show the improvements obtained by using array interpolation methods, i.e. techniques able to create a virtual array response out of the actual array one, such as to comply with the algorithms’ requirements on the antenna response. © 2017 IEEE.
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| 4. |
- Campion, James, et al.
(författare)
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Elliptical alignment holes enabling accurate direct assembly of micro-chips to standard waveguide flanges at sub-THz frequencies
- 2017
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Ingår i: 2017 IEEE MTT-S International Microwave Symposium (IMS). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509063604 ; , s. 1262-1265
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Konferensbidrag (refereegranskat)abstract
- Current waveguide flange standards do not allow for the accurate fitting of microchips, due to the large mechanical tolerances of the flange alignment pins and the brittle nature of Silicon, requiring greatly oversized alignment holes on the chip to fit worst-case fabrication tolerances, resulting in unacceptably large misalignment error for sub-THz frequencies. This paper presents, for the first time, a new method for directly aligning micromachined Silicon chips to standard, i.e. unmodified, waveguide flanges with alignment accuracy significantly better than the waveguide-flange fabrication tolerances, through the combination of a tightly-fitting circular and an elliptical alignment hole on the chip. A Monte Carlo analysis predicts the reduction of the mechanical assembly margin by a factor of 5.5 compared to conventional circular holes, reducing the potential chip misalignment from 46 μm to 8.5 μm for a probability of fitting of 99.5%. For experimental verification, micromachined waveguide chips using either conventional (oversized) circular or the proposed elliptical alignment holes were fabricated and measured. A reduction in the standard deviation of the reflection coefficient by a factor of up to 20 was experimentally observed from a total of 200 measurements with random chip placement, exceeding the expectations from the Monte Carlo analysis. To our knowledge, this paper presents the first solution for highly accurate assembly of micromachined waveguide chips to standard waveguide flanges, requiring no custom flanges or other tailor-made split blocks.
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| 5. |
- 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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| 6. |
- Frank, Markus, 1970, et al.
(författare)
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Lumped element balun with inherent complex impedance transformation
- 2017
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Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781509063604 ; , s. 1285-1288
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Konferensbidrag (refereegranskat)abstract
- A novel lumped design approach for complex impedance transforming baluns is presented in this paper. It is shown that a relaxation of symmetry in the T-networks of the out-of-phase-compensated-power-splitter enables complex impedance transformation. Design equations are analytically derived for a total of 4 component values, of which 2 values depend upon the 2 other, which are free variables. The two free component values are used independently for adjustment of input reflection loss, further keeping the balance parameter maximally flat and independent of the load impedance. For Q-values of source and load, not being excessively high, the balun can be realized with only 8 components. A demonstrator is fabricated, transforming 26.9 + j11.1 Ω to 73.8 + j38.6 Ω. An amplitude balance of ±0.7 dB and phase balance better than ±5° is achieved over a 20 % bandwidth. The return loss is higher than 20 dB.
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| 7. |
- Glubokov, Oleksandr, 1985-, et al.
(författare)
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Micromachined Multilayer Bandpass Filter at 270 GHz Using Dual-Mode Circular Cavities
- 2017
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Ingår i: 2017 IEEE MTT-S International Microwave Symposium. - : IEEE conference proceedings. - 9781509063604 ; , s. 1449-1452
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Konferensbidrag (refereegranskat)abstract
- In this paper, we present a microfabricated fourth-order sub-THz WR-3.4 bandpass waveguide filter based on TM110 dual-mode circular-shaped cavity resonators. The filter operates at the center frequency of 270 GHz with fractional bandwidth of 1.85% and two transmission zeros are introduced in the upper and in the lower stopband using a virtual negative coupling. The microchip filter is significantly more compact than any previous dual-mode designs at comparable frequencies, occupying less than 1.5 mm2. Furthermore, in contrast to any previous micromachined filter work, due to its axially arranged interfaces it can be directly inserted between two standard WR-3.4 rectangular-waveguide flanges, which vastly improves system integration as compared to previous micromachined filters; in particular no custom-made split-block design is required. The cavities are etched in the handle layer of a silicon-on-insulator (SOI) wafer, and coupling is realized through rectangular slots fabricated in the SOI device layer. Couplings of the degenerate modes in one cavity are facilitated by means of small perturbations in the circular cavity shapes. The measured average return loss in the passband is –18 dB and worst-case return loss is –15 dB, and an insertion loss of only 1.5 dB was measured. The excellent agreement between measured and simulated data is facilitated by fabrication accuracy, design robustness and micromachined self-alignment geometries.
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| 8. |
- Habibpour, Omid, 1979, et al.
(författare)
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Generation of multi-Gigabit/s OFDM signals at W-band with a graphene FET MMIC mixer
- 2017
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Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781509063604 ; , s. 1185-1187
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Konferensbidrag (refereegranskat)abstract
- This paper presents multi-Gigabit/s Orthogonal Frequency Division Multiplexing (OFDM) signal generation by using a graphene field effect transistor based resistive mixer at w-band. The OFDM signals consist of 64 subcarriers each carrying a quadrature-phase-shift-keying (QPSK) symbols. The results show that a bit error rate of 10 -4 is achievable for 8 Gbps data rate.
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| 9. |
- Hanning, Johanna, 1981, et al.
(författare)
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A Broadband THz Waveguide-to-suspended Stripline Loop-probe Transition
- 2017
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Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781509063604 ; , s. 1091-1094
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Konferensbidrag (refereegranskat)abstract
- We present a novel waveguide-to-suspended stripline loop-probe transition operating over the entire WR-1.0 waveguide band. The loop probe is designed for broadband response with simulated RL > 15 dB, and has an integrated DC return path, which can also be extended for biasing. The measured insertion loss for a back-to-back configuration is 1 – 2 dB in almost the entire frequency range of 750 – 1100 GHz.
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| 10. |
- Hassona, Ahmed Adel, 1988, et al.
(författare)
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A non-galvanic D-band MMIC-to-waveguide transition using eWLB packaging technology
- 2017
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Ingår i: 2017 IEEE MTT-S International Microwave Symposium (IMS). - : Institute of Electrical and Electronics Engineers (IEEE). - 0149-645X. - 9781509063604 ; , s. 510-512
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Konferensbidrag (refereegranskat)abstract
- This paper presents a novel D-band interconnect implemented in a low-cost embedded Wafer Level Ball Grid Array (eWLB) commercial process. The non-galvanic transition is realized through a slot antenna directly radiating to a standard air filled waveguide. The interconnect achieves low insertion loss and relatively wide bandwidth. The measured average insertion loss is 3 dB across a bandwidth of 22% covering the frequency range 110138 GHz. The measured average return loss is -10 dB across the same frequency range. Adopting the low-cost eWLB process and standard waveguides makes the transition an attractive solution for interconnects beyond 100 GHz. This solution enables mm-wave system on chip (SoC) to be manufactured and assembled in high volumes cost effectively. To the authors' knowledge, this is first attempt to fabricate a packaging solution beyond 100 GHz using eWLB technology.
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