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A design methodology for a concurrent dual-band Doherty power amplifier (PA) with frequency-dependent backoff power ranges is presented in this paper. Based on a dual-band T-shaped network and a coupled line network, different dual-band components needed in Doherty PA topology, including a 3-dB branch-line coupler, an offset line, and a quarter-wavelength(More)
The behavior of power amplifiers (PAs) driven by concurrent dual-band signals is analyzed theoretically in this paper. According to the analysis, the impedance matching at intermodulation (IM) frequency is very important for PAs working in concurrent mode. Based on the concept of IM impedance tuning, a family of new operation modes can be introduced,(More)
In this paper, we consider a two-way or bi-directional communications system with a relay equipped with multiple antennas. We show that when the downlink channel state information is not known at the relay, the benefit of having additional antennas at the relay can only be obtained by using decode and forward (DF) but not amplify and forward (AF). The gain(More)
Cross-band modulation effects in the concurrent dual-band transmitters are quite noticeable for the linearization. This paper proposes a novel two-dimensional modified memory polynomial (2D-MMP) technique to compensate for nonlinear distortion in the concurrent dual-band transmitters. By taking into account the cross-band modulation effects, the 2D-MMP(More)
This paper demonstrates an energy-efficient and low-complexity subsampling receiver adopted in the feedback loop of the dual-band power amplifier (PA) linearization architecture. The challenges and issues on finding the valid subsampling frequencies in nonlinear system are discussed, and a systematic approach for finding valid subsampling frequencies is(More)
OBJECTIVES The aim of the study is to assess the clinical value of 16-row multislice computed tomographic angiography (CTA) for detection and treatment of intracranial aneurysms. PATIENTS AND METHODS Between January 2005 and October 2008, 388 patients were included and successively underwent 16-slice CTA for suspected intracranial aneurysms. Three(More)