A 200 W broadband high power amplifier using hybrid power combining network and digital level control

Abstract

In this article, a 2 to 6 GHz solid‐state power amplifier with 53 dBm output power has been analyzed, designed, and fabricated. To achieve a wideband high output power, we introduce a 16‐way hybrid power combiner based on microstrip planar binary and parallel structures. The simulation and measurement results of the proposed hybrid power combining network (PCN) show that the maximum power combining efficiency is around 86% with the insertion loss of around 0.6 to 1.5 dB and an isolation of 20 dB between the ports. Also, to compensate the output power variations due to the thermal and operating frequency changes across the bandwidth, a digital level control (DLC) unit utilizing an agile control algorithm is proposed which decreases the output power variations to 2% of the desired output power. A cooling heatsink fan system has been also designed in order to transfer the heat generated power to the air. The measured output power for the applied input continuous wave is higher than 52.5 dBm. In addition, the power added efficiency (PAE) is better than 15% across the wide portion of the bandwidth and the measured third‐order intermodulation is about 20 dBc (average).

A power amplifier by using asymmetrical branch-line coupler

“…Port 1 is used as an output terminal with 50 Ω, port 2 is used as an isolated terminal, port 3 and port 4 are used as input terminal with 90 °phase difference. 3-dB directional coupler, works as a power combiner, is a common component in high-power amplifier design process [21,24]. In this case, the parameters of the asymmetrical branch-line coupler are…”

“…Generally, traditional high-power PAs in radar system usually consist of the output matching circuits and power combining circuits [21,22,23,24,25]. These two circuits are designed separately, and exploited a good performance in high-power PAs.…”

A high‐efficiency 50 W X‐band GaN power amplifier in hybrid MIC technology

“…Moreover, their long lifetime and ease of maintenance make the design of high‐power amplifiers using single GaN‐HEMT bare‐dies possible and hence make them the right candidate for space applications 1‐4 . Since then, numerous SSPA designs based on GaN HEMTs are reported from lower frequency bands, 5‐13 to X ‐ and Ku ‐bands, 14‐16 and even upper bands 17 …”

“…Moreover, their long lifetime and ease of maintenance make the design of high-power amplifiers using single GaN-HEMT bare-dies possible and hence make them the right candidate for space applications. [1][2][3][4] Since then, numerous SSPA designs based on GaN HEMTs are reported from lower frequency bands, [5][6][7][8][9][10][11][12][13] to X-and Ku-bands, [14][15][16] and even upper bands. 17 Different technologies, such as monolithic microwave integrated circuits (MMICs), and hybrid integration techniques based on bare-dies have been used for the realization of high-frequency SSPAs.…”