Revistas
Revista:
IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS
ISSN:
1531-1309
Año:
2021
Vol.:
31
N°:
2
Págs.:
157 - 160
This letter presents the design of a 140-160 GHz vector-modulator-type phase shifter, integrated in a 55-nm BiCMOS technology. The circuit is optimized to minimize the occupied area and maximize the linearity, facilitating its integration in D-band phased arrays. Test results show an average insertion loss of 4.5 dB, an OP 1 dB of -3.7 dBm, and rms gain/phase errors lower than 1.4 dB and 7.5 degrees. The circuit core occupies 0.05 mm(2), consuming less than 66 mW of dc power.
Revista:
POWDER METALLURGY
ISSN:
0032-5899
Año:
2021
Vol.:
64
N°:
4
Págs.:
331 - 340
Different approaches to take advantage of powder metallurgy in the manufacturing of diamond-impregnated components were studied. Three different powders were used as starting materials; two pre-alloyed powders, based on Fe-Cu and Fe-Cu-Sn systems, and one pre-mixed Fe-based powder. Different manufacturing routes as a strategy to obtain tailored mechanical properties were studied, with the influence of alloying elements such as graphite, iron phosphide and Mn-Ni-B master alloy to reinforce the iron-based powders. Both uncoated and coated commercial synthetic diamonds were introduced in the systems to analyse the surface reactions that depend on both metallic matrix and processing parameters. Hardness values from 88 to 105 HRB were obtained with a wide range of transverse rupture strength values from 1250 to 1640 MPa. An appropriate combination of metallic matrix, alloying elements and processing parameters makes the materials analysed here suitable powders for the manufacturing of diamond-impregnated tools.
Revista:
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
ISSN:
0018-9480
Año:
2020
Vol.:
68
N°:
1
Págs.:
339 - 351
Changes in ambient temperature or chip temperature result in variations in the in-phase and quadrature (I/Q) gain and phase imbalance. As a consequence, the overall system performance can be seriously degraded, especially in wideband multi-Gb/s systems, where the I/Q imbalance is highly selective in frequency. Unless appropriately considered, temperature drifts can decrease the image rejection ratio (IRR) of the transmitter. This article presents a novel compensation method for temperature-dependent transmitter I/Q imbalance over the entire temperature range. It consists of a simple predistortion technique that, based on a few factory characterizations of gain and phase imbalance, is able to estimate and correct the I/Q imbalance at any temperature, without interrupting the normal functionality of the system. The proposed method is assessed in a 2-GHz, 64-QAM transceiver implemented with real hardware. The measurements show that the proposed approach is able to keep the IRR greater than 35 dB in the entire bandwidth and an error vector magnitude (EVM) lower than 3 over a temperature range of 70 C.
Revista:
IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS
ISSN:
1531-1309
Año:
2019
Vol.:
29
N°:
5
Págs.:
351 - 353
This letter presents the design of a compact, wideband, and high-efficiency E-band power amplifier, integrated in a 0.13-mu m BiCMOS process and occupying 0.3 mm(2). It consists of a single-stage balanced amplifier, with HBT transistors in cascode configuration. The power amplifier (PA) is biased in class AB, with a dc consumption of 156 mW. A compact bias circuit is employed to achieve temperature robustness, while the layout is optimized for wideband and highly efficient operation. Measurements show a peak power gain of 15.3 dB at 83 GHz, with a 29.3% fractional bandwidth and less than 1-dB degradation over a 25 degrees C-85 degrees C temperature range. The peak output power at saturation and 1-dB compression is 18.6 and 13.6 dBm, respectively, and the maximum power-added efficiency (PAE) is 30.7%.
Revista:
INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS
ISSN:
0098-9886
Año:
2018
Vol.:
46
N°:
3
Págs.:
366 - 374
This paper presents the design of a compact and wide bandwidth millimeter-wave power detector, integrated at the output of an E-band power amplifier and implemented in a 55-nm SiGe BiCMOS process. It is based on a nonlinear PMOS detector core, and its measured output voltage tracks the output power of the PA from 67 to 90GHz. It provides an insertion loss lower than 0.2dB, and its responsivity can be tuned between 8 and 17V/W. The output bandwidth is bigger than 3GHz, which allows built-in self-test when transmitting multigigabit millimeter-wave signals.
Revista:
IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS
ISSN:
1531-1309
Año:
2017
Vol.:
27
N°:
5
Págs.:
512 - 514
This letter presents a 15-21 GHz I/Q upconverter, based on two Gilbert-cell mixers with an on-chip wideband linearization loop that extends the linear region and allows power efficient operation at backoff power levels. A quadrature LO signal is generated using an integrated two-stage polyphase filter. Measurements show a conversion gain of -5.5 dB, an output 1-dB compression point of 0 dBm, and an image suppression of 40 dB over the 6-GHz output bandwidth. An error vector magnitude of 3.5% is obtained for a 10-Gb/s 64-QAM signal with a bandwidth of 2 GHz. The circuit is integrated in a 55-nm BiCMOS process and occupies 1.07 mm2. The dc power consumption is 61 mW.
Revista:
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
ISSN:
0018-9480
Año:
2017
Vol.:
65
N°:
8
Págs.:
2990 - 3001
This paper presents the design of a wideband and high-linearity E-band transmitter integrated in a 55-nm SiGe BiCMOS technology. It consists of a double-balanced bipolar ring mixer which upconverts a 16-21-GHz IF signal to the 71-76- and 81-86-GHz bands by the use of a 55/65-GHz local oscillator signal, followed by a broadband power amplifier which employs 2-way output power combining using an integrated low-loss balun transformer. The transmitter exhibits an average conversion gain of 24 dB and 22 dB at the 71-76- and 81-86-GHz bands, respectively, with an output 1-dB compression point greater than 14 and 11.5 dBm at each band. A maximum output power of 16.8 dBm is measured at 71 GHz. The dc power consumption is 575 mW. The presented transmitter is used to demonstrate the transmission of a 10.12-Gb/s 64 quadrature amplitude modulated signal with a spectral efficiency of 5.06 bit/s/Hz, which makes it suitable for use in future highcapacity backhaul and fronthaul point-to-point links.
Revista:
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
ISSN:
0018-9480
Año:
2017
Vol.:
65
N°:
11
Págs.:
4758 - 4769
This paper addresses the estimation and compensation of I/Q imbalance, one of the most prominent impairments found in wideband zero-intermediate frequency transceivers (TRxs). The I/Q imbalance encountered in this kind of TRx comprises not only frequency-selective gain and phase imbalance but also delay imbalance. Unless appropriate compensation is applied, the I/Q imbalance significantly degrades the performance of a communication system. This paper presents a novel compensation technique for transmitter I/Q imbalance based on built-in-self-calibration, a low cost and robust compensation technique that enables manufacturing as well as in-field calibration with low computational complexity. The method's performance is evaluated in a TRx with 64-quadratic-amplitude modulation and 2 GHz of bandwidth implemented with real hardware. The measurements show that the proposed technique achieves an image rejection ratio greater than 35 dB in the entire 2 GHz bandwidth and an error vector magnitude lower than 3%.
Revista:
INTEGRATION-THE VLSI JOURNAL
ISSN:
0167-9260
Año:
2016
Vol.:
52
Págs.:
208 - 216
This paper describes a method to design mmW PAs, by modeling the electromagnetic behavior of all the passive structures and the layout interconnections using a 3D-EM solver. It allows the optimization of the quality factor of capacitors (Q-factors > 20 can be obtained at 80 GHz), the access points and arrangement of the power transistor cells. The method is applied to the design and optimization of an E-Band PA implemented in a 55 nm SiGe BiCMOS technology. The PA presents a maximum power gain of 21.7 dB at 74 GHz, with a 3-dB bandwidth covering from 72.6 to 75.6 GHz. The maximum output P1dB is 13.8 dBm at 75 GHz and the peak PAE is 14.1%. (C) 2015 Elsevier B.V. All rights reserved.
Revista:
INTERNATIONAL JOURNAL OF COMMUNICATION
ISSN:
1998-4480
Año:
2015
Vol.:
9
Págs.:
98 - 104
Revista:
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS
ISSN:
0895-2477
Año:
2012
Vol.:
54
N°:
4
Págs.:
909 - 915
This article presents two rat-race 180 degrees ring hybrid couplers that operate on ultra wide band at the frequency range of 3 to 10 GHz. All pass coplanar strip structure, based on one of the ten canonical coupled line circuits, is proposed for the ?/4 sections [1, 2], and two-metal structure on suspended substrate [3] is used to improve the return-losses of hybrid. Besides the two end-shorted coupled lines for the 3?/4 section, which is already known to broaden the narrowband behaviour of the traditional rat-race ring [4], a three-coupled lines structure [5] was studied as a design alternative. This hybrid could be used in a UWB low cost passive mixer with the advantage of maximizing the available space for the mixing devices and their associated circuitry, leaving free the internal area of the hybrid on the both sizes of the substrate. Consequently, the total size of the complete mixer is minimised and the compactness improved. The low coast approach is remarked by the use of standard FR-4 laminate. (c) 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:909915, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26718
Revista:
PROGRESS IN ELECTROMAGNETICS RESEARCH LETTERS
ISSN:
1937-6480
Año:
2012
Vol.:
35
Págs.:
63 - 72
A new high isolation lumped-element 180º hybrid, using electronically adjustable filters with varactor diodes, are proposed. This design is very simple and is based on only two configurable low order (N = 2) filters. Due to the limited tuning frequency range of varactor diodes, maximum near-octave frequency coverage of 2.5-5 GHz was planned in the high isolation hybrid. An impressive simulated typical isolation in the range of >60dB was achieved. One of the typical applications of developed hybrids could be the conversion of 70MHz IF to microwave frequencies, with broadband mixers in single-conversion converters, and with very high LO rejection (>60 dB)
Revista:
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS
ISSN:
0895-2477
Año:
2011
Vol.:
53
N°:
12
Págs.:
2742 - 2746
Transmitting antenna in a Railway Spot Signalling System needs to be optimized in order to ensure data transfer reliability and minimize the required power. This paper analyses the improvement of the HF transmitting antenna taking into account the size of the receiving antenna, the presence of metallic objects and the misalignment between transmitting and receiving antennas. A novel HF transmitting antenna structure is proposed and verified to improve the read range.
