A 1V power amplifier for 81-86 GHz E-band
Author
Summary, in English
The design and layout of a two stage SiGe E-band power amplifier using a stacked transformer for output power combination is presented. In EM-simulations with ADS Momentum, at E-band frequencies, the power combiner consisting of two individual single turn transformers performs significantly better than a single 2:1 transformer with two turns on the secondary side. Imbalances in the stacked transformer structure are reduced with tuning capacitors for maximum gain and output power. At 84 GHz the simulated loss of the stacked transformer is as low as 1.35 dB, superseding the performance of an also presented alternative power combiner. The power combination allows for a low supply voltage of 1 V, which is beneficial since the supply can then be shared between the power amplifier and the transceiver, thereby eliminating the need of a separate voltage regulator. To improve the gain of the two-stage amplifier it employs a capacitive cross-coupling technique not yet seen in mm-wave SiGe PAs. Capacitive cross-coupling is an effective technique for gain enhancement but is also sensitive to process variations as shown by Monte Carlo simulations. To mitigate this two alternative designs are presented with the cross coupling capacitors implemented either with diode coupled transistors or with varactors. The PA is designed in a SiGe process with f T = 200 GHz and achieves a power gain of 12 dB, a saturated output power of 16 dBm and a 14 % peak PAE. Excluding decoupling capacitors it occupies a die area of 0.034 mm2.
Department/s
Publishing year
2014
Language
English
Pages
335-348
Publication/Series
Analog Integrated Circuits and Signal Processing
Volume
80
Issue
3
Document type
Journal article
Publisher
Springer
Topic
- Electrical Engineering, Electronic Engineering, Information Engineering
Keywords
- Power amplifier
- E-band
- mm-wave
- Transformers
- EM-simulation
- Capacitive cross coupling
Status
Published
Research group
- Analog RF
ISBN/ISSN/Other
- ISSN: 0925-1030