Khaled Bathich

Wideband harmonically-tuned GaN Doherty power amplifier

This paper presents the design of a wideband harmonically-tuned Doherty amplifier. The frequency-dependent back-off efficiency degradation was minimized by compensating the effect of the frequency-sensitive impedance inverters over the design band. Suitable choice of device size ratio as well as harmonic load tuning at back-off and maximum power operations were also considered, resulting in superior performance over the targeted design band. The maximum output power ranged from 48.2 dBm to 49.6 dBm. 6 dB back-off efficiencies of η6dB≥53 % (power-added efficiency PAE≥50 %) were measured over 1.7–2.25 GHz (28 % bandwidth). When linearized using digital pre-distortion (DPD), the Doherty amplifier had adjacent-channel leakage ratio (ACLR) of −43 dBc for a long-term evolution (LTE) signal at 1.85 GHz (η=50 %) and −44 dBc for a wideband code-division multiple access (W-CDMA) signal at 2.11 GHz (η=41 %), at average output power of 41.0 dBm and 40.5 dBm, respectively.

100 W highly efficient octave bandwidth GaN-HEMT power amplifier

In this contribution, the design, implementation, and experimental results of a high-efficiency broadband GaN HEMT power amplifier are presented. Optimum fundamental and harmonic load impedances were obtained using load-pull simulations for the active device across the design bandwidth. A systematic approach was applied for the design of wideband output and input matching networks. Continuous wave (CW) large-signal measurement results showed that across 1.1-2.0 GHz (58 % bandwidth), the output power was higher than 110 W, and 50-72% drain efficiency was achieved. Over the octave bandwidth of 1.0-2.0 GHz, at least 84 W output power was measured. The power gain was around 12 dB. An ACLR of -45 dBc was measured for an LTE signal at 42 dBm average output power under additional digital predistortion (DPD).

A high efficiency Si LDMOS Doherty power amplifier with optimized linearity

This paper presents a high efficiency uneven UMTS Doherty power amplifier (DPA) based on Si LDMOS technology. An optimum output combining network was designed to enhance the efficiency at backoff power. High efficiency Si LDMOS transistors were used for the DPA design. The designed DPA has a maximum output power of Psat=39.7 dBm (9.4 W). A maximum drain efficiency of ηmax=54 % (PAEmax=40 %) was measured. The efficiency was maintained above ?=40 % (PAE =36 %), over 6 dB backoff, and above η=32 % (PAE=30 %), over 9 dB backoff, relative to the maximum (saturated) output power. The designed PA was experimentally optimized to enhance its linearity. For a 1-carrier W-CDMA test signal, an ACPR of −44 dBc was measured at an average output power of Pout=30.7 dBm.

A 6W Uneven LDMOS Doherty Power Amplifier With High Efficiency for GSM900 Base Stations

In this paper, a 6W uneven LDMOS Doherty power amplifier (DPA), designed for GSM900 base stations, which implement phased antenna array transmission, is presented. The designed Doherty PA can deliver a maximum power of 6.5W. A high drain efficiency of ¿=64% (PAE=58%) is measured. The efficiency is maintained above ¿=43% (PAE=37%), over 6-dB output backoff, and above ¿=31% (PAE=29%), over 9-dB output backoff, related to the maximum (saturated) power.

A 2 GHz, 85W Uneven GaN Doherty power amplifier

Modern wireless communication standards, e.g. UMTS, are making use of modulation schemes, resulting in signals with high levels of peak-to-average power ratio (PAR). For example, the W-CDMA signal used in UMTS-standard has typical PAR levels above 6 dB. Conventional single-ended power amplifiers will result in low levels of average efficiency, if they were implemented in the transmitters of such communication systems. Furthermore, power control in cellular communication networks is a crucial requirement, in both, base station and handset transmitters, to reduce the operating cost on the base station side, and to minimize the adjacent-channel interference. It is though apparent, that power amplifiers in modern wireless communication networks, should operate over a wide output back off region, with high levels of efficiency, maintained over the power operating range. The Doherty power amplifier technique is a competitive solution for efficiency enhancement, which has been recently widely investigated, due to its relatively simple circuitry and ease of implementation.