Accurate modelling of cold-MESFETs for adaptive MMIC signal processing applications

Lucyszyn, S.; Oztek-Yerll, C F; Robertson, I.D.

doi:10.1109/euma.1995.337150

Cited by 4 publications

(2 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The balanced modulator employs two reflectiontype modulators operated in a push-pull mode [9], [10], [19], [20]. The input signal is effectively split using a balun, and the outputs from each branch, which are driven with complimentary control voltages ( and ), are combined inphase.…”

Section: Balanced Modulatormentioning

confidence: 99%

Direct multilevel carrier modulation using millimeter-wave balanced vector modulators

Ashtiani

Nam

d'Espona

et al. 1998

IEEE Trans. Microwave Theory Techn.

View full text Add to dashboard Cite

The importance of being able to design affordable, high-performance, millimeter-wave transmitters for digital communications and radar applications is increasing. To this end, two monolithic millimeter-wave vector modulators have been realized at 38 and 60 GHz for use in direct multilevel carrier modulation. It is shown that, by employing balanced biphase amplitude modulator elements, accurate constellations are achieved with broad-band operation from 20 to 40 GHz and 55 to 65 GHz. Modulations of 16-and 256-QAM have been demonstrated, both at 38 and 60 GHz, using this technique. Each balanced biphase amplitude modulator uses a pair of reflection-type attenuators operated in push-pull mode. This study investigates the suitability of this topology for use as a full biphase amplitude modulator for multilevel digital modulation schemes. It is found that the technique is very robust and the resulting analog vector modulator can be a very important component for many future millimeter-wave applications.

show abstract

Section: Balanced Modulatormentioning

confidence: 99%

Direct multilevel carrier modulation using millimeter-wave balanced vector modulators

Ashtiani

Nam

d'Espona

et al. 1998

IEEE Trans. Microwave Theory Techn.

View full text Add to dashboard Cite

show abstract

“…Cold MESFET's have been accurately characterized at microwave frequencies [23] and subsequently deployed in numerous MMIC applications ranging from reflection topology building blocks for adaptive microwave signal-processing applications [3] (including variable beam-forming networks [4] to tunable active inductors used in tunable active bandpass filters [24] and tunable notch filters [25]). A microphotograph of the MMIC biphase modulator is shown in Fig.…”

Section: A Mesfet-based Attenuatormentioning

confidence: 99%

Optically induced measurement anomalies with voltage-tunable analog-control MMIC's

Lucyszyn

Robertson

1998

IEEE Trans. Microwave Theory Techn.

View full text Add to dashboard Cite

Monolithic microwave integrated circuits (MMIC's) may be measured under relatively high-intensity lighting conditions. Later, when they are packaged, any anomalies found in subsequent measurements could be attributed to unwanted parasitics or box modes associated with the packaging. However, optical effects may not always be considered by radiofrequency (RF) and microwave engineers. For the first time, a qualitative assessment is given for the effects of photonic absorption on three broad-band voltage-tunable analog-control circuits. Each circuit has a different function, with each fieldeffect transistor (FET) operating in a different mode: a hot FET in a variable-gain amplifier, a cold FET in an analog attenuator, and an FET varactor in an analog phase shifter. All three circuit functions have been implemented using two different FETbased technologies. The first with ion-implanted 0.5-m GaAs metal-semiconductor FET's (MESFET's) in circuits operating at either 3 or 10 GHz. The second employs epitaxially grown 0.25-m AlGaAs/InGaAs pseudomorphic high electron-mobility transistors (HEMT's) in circuits operating at 38 GHz. All the MMIC's were fabricated using commercial foundry processes and illuminated under conventional optical microscope lighting conditions. Prominent error peaks have been found at bias points unique to the three different circuit topologies. Large error peaks are found with the MESFET-based circuits, while much smaller error peaks are achieved with the corresponding pseudomorphic HEMT (pHEMT) based circuits.

show abstract

Multi-level digital modulation performed directly at carrier frequency

Lucyszyn

Sewell²,

Robertson

1995

25th European Microwave Conference, 1995

Self Cite

View full text Add to dashboard Cite

Direct modulation of the carrier signal has been shown to be an attractive means of reducing the complexity of the RF hardware required in a communications transceiver. To this end, a proof-f concept X-band vector modulator, realised using monolithic phase shifters and attenuators, has been used to demonstrate that multi-level digital modulation can be implemented at high data rates and without requiring significant control power. The measured constellations for OPSK, 32-PSK and 16 CAM modulation are presented. This technique is suitable for both microwave and rrillimetre wave appicatons.

show abstract

Accurate modelling of cold-MESFETs for adaptive MMIC signal processing applications

Cited by 4 publications

References 5 publications

Direct multilevel carrier modulation using millimeter-wave balanced vector modulators

Direct multilevel carrier modulation using millimeter-wave balanced vector modulators

Optically induced measurement anomalies with voltage-tunable analog-control MMIC's

Multi-level digital modulation performed directly at carrier frequency

Contact Info

Product

Resources

About