An Outphasing Power Amplifier for a Software-Defined Radio Transmitter

Moloudi, S.; Takinami, Koji; Youssef, Michael; Mikhemar, Mohyee; Abidi, A.A.

doi:10.1109/isscc.2008.4523310

Cited by 49 publications

(19 citation statements)

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“…For example, the calculated output amplitude at frequency , , and gain, with of 1, 4, and 16 are plotted in Fig. 4, for (6) and (7) where is the input amplitude. Two interesting phenomena are observed when a large number of power generation unit is used.…”

Section: B Segmented Power Generationmentioning

confidence: 99%

“…This can be better understood in the context of inter-modulation distortion (IMD). The IMD product is calculated by substituting (8) into (6). The output amplitude of the third order IMD product (IMD3) at frequency or , is plotted in Fig.…”

Section: B Segmented Power Generationmentioning

confidence: 99%

“…However, similar to the Doherty amplifiers, it generally requires a phase shifter [13]. Although an out-phasing amplifier without using a shifter has been proposed at lower output power level [6], switches at the PA load can severely degrade its efficiency in a watt-level PA. Parallel processing of amplitude and phase information (e.g., EER or polar modulation) has also been proposed as a way of improving the system power efficiency [14].…”

mentioning

confidence: 99%

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An octave-range watt-level fully integrated CMOS switching power mixer array for linearization and back-off efficiency improvement

Kousai

Hajimiri

2009

2009 IEEE International Solid-State Circuits Conference - Digest of Technical Papers

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Section: B Segmented Power Generationmentioning

confidence: 99%

Section: B Segmented Power Generationmentioning

confidence: 99%

mentioning

confidence: 99%

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An octave-range watt-level fully integrated CMOS switching power mixer array for linearization and back-off efficiency improvement

Kousai

Hajimiri

2009

2009 IEEE International Solid-State Circuits Conference - Digest of Technical Papers

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“…Although the RF performance of semiconductors like GaN and GaAs is very high as compared to CMOS, but they are preferred in high-requirement applications, such as RBS and satellite applications. Fully integrated CMOS wireless transceiver have become quite common for portable devices [26,27].…”

Section: Fabrication Technology For Rf Pasmentioning

confidence: 99%

“…The output signal distortion can be reduced by varying the output capacitance and the power supply such that they compensate the load variations at the PA outputs due to outphasing angle [26,27].…”

Section: Combinermentioning

confidence: 99%

Pulse-Width Modulated RF Transmitters

Haque¹

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To my mother, father, and uncle (mamoo), AbstractThe market for wireless portable devices has grown significantly over the recent years. Wireless devices with ever-increased functionality require high rate data transmission and reduced costs. High data rate is achieved through communication standards such as LTE and WLAN, which generate signals with high peak-to-average-power ratio (PAPR), hence requiring a power amplifier (PA) that can handle a large dynamic range signal. To keep the costs low, modern CMOS processes allow the integration of the digital, analog and radio functions on to a single chip. However, the design of PAs with large dynamic range and high efficiency is challenging due to the low voltage headroom.To prolong the battery life, the PAs have to be power-efficient as they consume a sizable percentage of the total power. For LTE and WLAN, traditional transmitters operate the PA at back-off power, below their peak efficiency, whereas pulse-width modulation (PWM) transmitters use the PA at their peak power, resulting in a higher efficiency. PWM transmitters can use both linear and SMPAs where the latter are more power efficient and easy to implement in nanometer CMOS. The PWM transmitters have a higher efficiency but suffer from image and aliasing distortion, resulting in a lower dynamic range, amplitude and phase resolution.This thesis studies several new transmitter architectures to improve the dynamic range, amplitude and phase resolution of PWM transmitters with relaxed filtering requirements. The architectures are suited for fully integrated CMOS solutions, in particular for portable applications.The first transmitter (MAF-PWMT) eliminates aliasing and image distortions while allowing the use of SMPAs by combining RF-PWM and band-limited PWM. The transmitter can be implemented using all-digital techniques and exhibits an improved linearity and spectral performance. The approach is validated using a Class-D PA based transmitter where an improvement of 10.2 dB in the dynamic range compared to a PWM transmitter for a 1.4 MHz of LTE signal is achieved.The second transmitter (AC-PWMT) compensates for aliasing distortion by combining PWM and outphasing. It can be used with switch-mode PAs (SMPAs) or linear PAs at peak power. The proposed transmitter shows better linearity, improved spectral performance and increased dynamic range as it does not suffer from AM-AM distortion of the PAs and aliasing distortion due to digital PWM. The idea is validated using push-pull PAs and the proposed transmitter shows an improvement of 9 dB in the dynamic range as compared v vi Abstract to a PWM transmitter using digital pulse-width modulation for a 1.4 MHz LTE signal.The third transmitter (MD-PWMT) is an all-digital implementation of the second transmitter. The PWM is implemented using a Field Programmable Gate Array (FPGA) core, and outphasing is implemented as pulse-position modulation using FPGA transceivers, which drive two class-D PAs. The digital implementation offers the flexibility to adapt the transmitter...

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Microstrip Passive Elements

Edwards¹,

Steer²

2016

Foundations for Microstrip Circuit Design

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An Outphasing Power Amplifier for a Software-Defined Radio Transmitter

Cited by 49 publications

References 2 publications

An octave-range watt-level fully integrated CMOS switching power mixer array for linearization and back-off efficiency improvement

An octave-range watt-level fully integrated CMOS switching power mixer array for linearization and back-off efficiency improvement

Pulse-Width Modulated RF Transmitters

Microstrip Passive Elements

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