High-gain GaN doherty power amplifier for Ka-band satellite communications

Source/Load-Pull Characterisation of GaN on Si HEMTs with Data Analysis Targeting Doherty Design

“…To fulfil the linearity requirements of advanced multi-carrier mudulation schemes, the PA must operate in back-off, meaning a large efficiency reduction in conventional PAs. Hence, the adoption of efficiency enhancement solutions such as the Doherty power amplifier (DPA) [3], [4] is researched for satellite applications [5].…”

Future technologies for very high throughput satellite systems

“…Considering the multicarrier signal nature and the large envelope peak‐to‐average power ratio (PAPR), the SSPA efficiency must be optimized at the desired operating point and with the large envelope PAPR. Nonstandard SSPA architectures, such Doherty HPAs, could provide an attractive way of improving efficiency. Microwave photonics offers high potential, especially for broadband applications thanks to extremely large bandwidth, –nearly lossless propagation in optical fiber within a spacecraft, –immunity to electromagnetic interference (EMI), and –lightweight, low volume, mechanically flexibility, galvanic isolation, and potential of integration into platform structures. For these reasons, microwave photonics components have been proposed to be implemented at various levels on‐board, linking equipment to equipment, board to board, or even chip to chip in photonic PCBs. On‐board digital processors will enable the flexibility in terms of beam‐forming, channelization, and routing with improvement needed on high‐speed and low‐power A/D and D/A converters, –high‐speed serial links (intraboards and interboards/equipment), –radiation‐tolerant ultra deep‐submicron application‐specific integrated circuit (ASIC) technology (high integration, low voltage, and low power), –high density packaging, –thermal management, –processor architecture/algorithm optimization, and –FPGAs/DSPs for reconfigurability. …”

“…Considering the multicarrier signal nature and the large envelope peak-to-average power ratio (PAPR), the SSPA efficiency must be optimized at the desired operating point and with the large envelope PAPR. Nonstandard SSPA architectures, such Doherty HPAs, 49 could provide an attractive way of improving efficiency.…”

Distortion mitigation for 100 and 250 MHz discrete supply modulation of a three-stage K-band MMIC PA

“…Published examples of GaN PAs at K-band exist in both commercial [1,2] and research processes [3][4][5][6][7]. Doherty amplifiers [8,9] and a single-ended linear amplifier [3] have also been designed in GaN at K-band to address back-off efficiency and linearity, respectively.…”

“…The SM shaping function is designed to increase efficiency while improving linearity over that of a PA with a static supply. We employ noise power ratio (NPR) as a linearity metric, widely accepted in the satellite communications community [1,9]. It is obtained by exciting the amplifier under test with a band-limited white noise signal with a narrow notch at the center and measuring the ratio between the average output power outside the notch and the average power in the notch created by intermodulation [25,26].…”