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In this paper, a novel Doherty power amplifier (DPA) configuration with a complex combining load (CCL) is presented to extend the high-efficiency range of the amplifier. Theoretical analysis of dynamic load span, current ratio, and drain efficiency reveals that CCL can offer a new degree of freedom to boost the output back-off (OBO) of the DPA. For verification, a 2-GHz equal-cell GaN HEMT-based DPA is simulated, prototyped, and measured with both complex and resistive combining loads (RCLs). Under continuous wave (CW) excitation, measurement results show that the proposed DPA can attain an OBO of 9.1 dB, which is 3.6 dB higher than that of the RCL design. In addition, by the use of single-carrier WCDMA signal with peak-to-average power ratio of 9.6 dB and at an average output power of 33.2 dBm, the proposed design is found to deliver an average drain efficiency of 57.4%. In the absence of multi-cell or enlarged auxiliary device, this approach offers a low-cost and simple DPA solution with extended OBO, as well as good Doherty behavior. [ABSTRACT FROM AUTHOR]

This paper presents a novel and simple linearization scheme for a CMOS double-balanced mixer based on the use of multibias dual-gate transistors. In this technique, intermodulation-distortion (IMD) components with proper phase relationship, generated by devices operating at different bias conditions, are combined together to improve the linearity of mixers. For experimental verification, the measured performance of a fabricated CMOS mixer is shown. Over 35 dB of IMD reduction is achieved by the proposed method under proper biasing condition. [ABSTRACT FROM AUTHOR]

Investigates the multistage amplifier linearization based on the generalized low-frequency signal-injection technique. Block diagram of the amplifying system; Intermodulation distortion components; Effects of gain error.

Presents a linearization scheme for radio frequency amplifiers based on simultaneous harmonic and baseband signal injection. Incorporation of second-order frequency components into the input of the main amplifier; Presentation of the analytical formulation of baseband, harmonic and the proposed injection techniques; Limitation of the proposed method.

Proposes a compact two-dimensional full-wave finite-difference frequency-domain method for general guided wave structures. Analysis of the dispersion characteristics of a general guided wave structure; Elimination of the longitudinal field components in the proposed method; Number of transverse field components in the resulting eigen equation.

A novel, current reused, voltage-controlled oscillator (VCO) and injection-locked frequency divider (ILFD) with variable dividing ratio is presented and implemented in UMC 0.18 \mum triple-well CMOS process. The proposed architecture allows compact and low power solution to be attained by the stacking of a ring-type ILFD and a transformer based VCO. The LC VCO provides the wideband differential output and the two-stage ring oscillator generates the quadrature output with selectable division ratios. Experimental results show an output frequency range from 0.58 to 3.11 GHz and a phase noise level of - 112.5~dBc/Hz at 1 MHz offset from carrier (5.72 GHz). This chip occupies a core area of 0.5\,\times\,0.3 mm^2 and consumes 4.7 mA from a 1.8 V power supply. [ABSTRACT FROM PUBLISHER]