Design of a Dual-Band PA for Millimeter-Wave 5G Applications (.PDF Download)

Considerable time and money are currently being invested in developing millimeter-wave technology for 5G, and there is much debate and lobbying in regard to the most suitable frequency bands for this application. In the U.S., the FCC has allocated licensed spectrum at 28 GHz, 37 GHz, and 39 GHz. In Europe, the Radio Spectrum Policy Group (RSPG) has recommended the 26-GHz band (24.25 to 27.5 GHz) as the pioneer band for 5G, with all the EU member states making a portion of this band available for 5G. It also recognized that the 32-GHz band (31.8 to 33.4 GHz) could be made available by many European administrations and effort should be made to keep it as an option for 5G in the future.

Development work is currently underway in all of these bands, and it is looking increasingly unlikely that a single band will be designated on a worldwide basis for millimeter-wave 5G in the immediate future. This means that the availability of dual-band or multi-band millimeter-wave components will become increasingly attractive. 

This article describes the design, layout, and performance of a dual-band power amplifier (PA) monolithic microwave integrated circuit (MMIC), capable of electronically switching its operating band between the 26-GHz and 32-GHz bands. The starting point was to undertake the preliminary design of two standalone PAs, each addressing one of the target bands. The targeted output power was 1 W at 1-dB gain compression (P1dB)—a commercially available 0.15-µm gate length pHEMT process was selected to achieve this. A three-stage design was implemented to achieve a small signal gain of around 20 dB.