Mitsubishi Electric and NanoSemi to demo ultra-wide-band linearized Doherty amplifier for next-gen LTE base stations

In booth 1827 at the IEEE MTT-S International Microwave Symposium (IMS2017) in Honolulu, Hawaii (6-8 June), Mitsubishi Electric US Inc of Cypress, CA is presenting a hands-on mini lab showcasing its high-efficiency, wide-band gallium nitride (GaN) Doherty amplifier.

Mitsubishi Electric Corp (Information Technology R&D Center and High Frequency and Optical Device Works), along with Mitsubishi Electric Research Laboratories, presented a paper at January’s Radio Wireless Week describing this wide-band Doherty power amplifier design technique for next generation LTE base stations using GaN transistor technology. The demonstration at IMS will further illustrate the ability to linearize an ultra-wideband signal applied to Mitsubishi Electric’s GaN power amplifier using an advanced pre-distortion technique provided by NanoSemi Inc of Waltham, MA, USA (which is exhibiting at IMS in booth #2030).

The proliferation of smartphones and tablets will require a dramatic increase in wireless capacity of base stations, notes Mitsubishi Electric. To meet this demand, mobile technologies are moving to next-generation LTE in which the wireless capacities are increased by allocating multiple simultaneous frequency bands (carrier aggregation) above 3GHz. Operating in multiple simultaneous frequency bands usually requires multiple power amplifiers to cover each frequency band, leading to an increase in the size of base stations.

Conventional base-station Doherty power amplifier design presents many challenges to simultaneously achieve both high efficiency and low distortion for wide-band carrier aggregation. Using NanoSemi’s digital pre-distortion (DPD) technology, Mitsubishi Electric’s wide-band Doherty power amplifier can achieve high efficiencies with up to 200MHz instantaneous bandwidth while maintaining adjacent channel level rejection (ACLR) of -50dBc. Base-station designers hence gain the ability to design a single flexible LTE power amplifier capable of many carrier aggregation scenarios, even above 3GHz, says the firm.

Mitsubishi Electric’s full line-up of GaN devices, with frequencies in the L-, S-, C-, and Ku-bands at output powers ranging from 2 to 100W, supports a variety of end-communications applications including cellular base-station, satellite, ground station and point to point.