| 1. |
- Anderberg, Martin, 1992, et al.
(författare)
-
A 183-GHz Schottky diode receiver with 4 dB noise figure
- 2019
-
Ingår i: IEEE MTT-S International Microwave Symposium Digest. - : IEEE. - 0149-645X. ; 2019-June, s. 172-175
-
Konferensbidrag (refereegranskat)abstract
- Atmospheric science based on space-borne millimeter wave measurements require reliable and state-of-the art receivers. In particular, the water vapor line at 183.3 GHz motivates the development of sensitive mixers at this frequency. Traditional assembly techniques employed in the production of Schottky diode receivers involve flip-chip mounting and soldering of discrete dies, which prohibit the implementation of reliable and repeatable production processes. In this work, we present a subharmonic 183 GHz mixer implementing a repeatable assembly method using beamlead Schottky diodes. The mixer was integrated with a InP HEMT MMIC low noise intermediate frequency amplifier resulting in a record-low receiver noise temperature of 450 K at 1 mW of local oscillator power measured at room-temperature. The measured Allan time was 10 s and the third order local oscillator spurious power was less than -60 dBm. The proposed assembly method is of particular importance for space-borne missions but also applicable to a wide range of terahertz applications.
|
|
| 2. |
- Baptista, Emanuel, 1993, et al.
(författare)
-
Analysis of thermal coupling effects in integrated MIMO transmitters
- 2017
-
Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781509063604 ; , s. 75-78
-
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.
|
|
| 3. |
- Bronders, Piet, et al.
(författare)
-
Measurement & Extraction of the Low-Frequency Dynamics of an Envelope Tracking Amplifier using Multisine Excitations
- 2018
-
Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. ; 2018-June, s. 1039-1042
-
Konferensbidrag (refereegranskat)abstract
- Both efficiency and linearity of an Envelope Tracking Power Amplifier depend on the tight synchronization between a Low- and High-Frequency path. The presence of reactive elements in this Low-Frequency path, as well as an inevitable delay difference between both paths, results in a dynamic mismatch that can seriously degrade the overall performance of the device. This work introduces a method that is able to extract these Low-Frequency dynamics without requiring access to any internal nodes of the device. The proposed extraction procedure makes use of the combination of a linear parameter-varying framework and a specific signal excitation strategy which uses a multisine excitation to mimic the operational conditions of the amplifier. A trustworthy model for the Low-Frequency dynamics is an important component necessary for building an adequate pre-distortion tool that is able to eliminate a bad dynamic match.
|
|
| 4. |
- Cabello Sánchez, Juan, 1992, et al.
(författare)
-
Multiline TRL Calibration Standards for S-parameter Measurement of Planar Goubau Lines from 0.75 THz to 1.1 THz
- 2018
-
Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. ; 2018-June, s. 879-882
-
Konferensbidrag (refereegranskat)abstract
- We present a multiline Thru-Reflect-Line (TRL) calibration standard for Planar Goubau Line (PGL) which allows setting the calibration plane along the PGL and thus removing the effect of the embedding structure. This opens the possibility of characterizing PGL-circuits. The presented structures were used for calibrating S-parameters measurements between 0.75 THz and 1.1 THz to characterize a 1 mm long and 10 µm wide PGL. The line shows negligible dispersion with an effective relative permittivity of 2.0 and an attenuation constant lower than 0.35 Np/mm (0.65 dB/λ).
|
|
| 5. |
- Cha, Eunjung, 1985, et al.
(författare)
-
Two-finger InP HEMT design for stable cryogenic operation of ultra-low-noise Ka-band LNAs
- 2017
-
Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781509063604 ; , s. 168-171
-
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.
|
|
| 6. |
- Dahlbäck, Robin, 1985, et al.
(författare)
-
Compact 340 GHz homodyne transceiver modules for FMWC imaging radar arrays.
- 2016
-
Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. ; 2016-August
-
Konferensbidrag (refereegranskat)abstract
- We present a solution where one single LO chain is used to feed a homodyne FMCW radar transceiver. An InGaAs pHEMT active frequency multiplier MMIC (x8) and a Schottky diode frequency doubler make up the LO chain. The novel Schottky diode based transceiver operates both as a frequency multiplier (x2) and as a sub-harmonic mixer. The modules operate at a center frequency of 340 GHz with a 30 GHz modulation bandwidth. An output power of 0 dBm, an IF noise level of -168 dBm/Hz and a receiver conversion loss of 18 dB is achieved in the band. The form factor of the modules is adapted to build one- or two- dimensional FMCW radar arrays. State of the art system performance is achieved while system complexity, size and cost is significantly reduced.
|
|
| 7. |
- Frank, Markus, 1970, et al.
(författare)
-
Lumped element balun with inherent complex impedance transformation
- 2017
-
Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781509063604 ; , s. 1285-1288
-
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.
|
|
| 8. |
- Gustafsson, Sebastian, 1990, et al.
(författare)
-
Vector-corrected Nonlinear Multi-port IQ-mixer Characterization using Modulated Signals
- 2017
-
Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. ; , s. 1433-1436
-
Konferensbidrag (refereegranskat)abstract
- In this paper, large-signal operation of IQ-mixers isstudied using a vector-corrected four-port measurement setup with modulated signals as stimuli. The measurement setup presents unique characterization possibilities since it has two ports at low/baseband frequencies and two ports at RF, making it ideal for characterization of frequency-translating devices such as mixers. A commercial upconverting IQ-mixer is studied, with the I and Q input signals residing at incommensurate frequencygrids, enabling separation of the nonlinear distortion generated in the I and Q branches. Frequency-domain and time-domain measurements reveal imbalances between the I and Q branches in terms of conversion gain and nonlinear distortion. It is also shown for the same mixer that operating the I and Q branches concurrently has limited influence on both conversion gain and nonlinear distortion, compared to non-concurrent operation.
|
|
| 9. |
- Habibpour, Omid, 1979, et al.
(författare)
-
Generation of multi-Gigabit/s OFDM signals at W-band with a graphene FET MMIC mixer
- 2017
-
Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781509063604 ; , s. 1185-1187
-
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.
|
|
| 10. |
- Hallberg, William, 1988, et al.
(författare)
-
Current scaled Doherty amplifier for high efficiency and high linearity
- 2016
-
Ingår i: IEEE MTT-S International Microwave Symposium Digest. - 0149-645X. - 9781509006984 ; 2016-August, s. Art. no. 7540185-
-
Konferensbidrag (refereegranskat)abstract
- In this paper, a novel Doherty power amplifier (PA) design method that enables high efficiency and high linearity simultaneously is developed. The output combiner network parameters are solved to satisfy boundary conditions required for high efficiency, and linear gain and phase responses. The proposed method is experimentally verified by a 2.14 GHz prototype PA, fabricated using two identical 15 W GaN HEMT devices. For a 8.6 dB peak to average power ratio 10 MHz LTE signal, the PA presents an average power added efficiency of 40%, and an adjacent power leakage ratio of -41 dBc without any linearization.
|
|
