Study on Volterra-Laguerre behavioral model for RF power amplifier

Voherra series behavioral model for radio frequency （RF） power amplifier （PA） has been widely used in system-level simulation, however, high computational complexity makes this kind of model limited to ＂weak＂ nonlinearity. In order to reduce the computational complexity and the number of coefficients of Volterra series kernels, a Volterra series improved behavioral model based on Laguerre orthogonal polynomials function, namely Voherra-Laguerre behavioral model, is proposed. Mathematical expressions of Volterra-Laguerre behavioral model is derived, and accuracy of the model is verified through comparison of measured and simulation output data from a freescale PA using MRF21030 transistor. Mathematical analysis and simulation results show that Voherra-Laguerre behavioral model has a simple structure, much less coefficients and better modeling performance than general Volterra series model. The model can be used more correctly for system-level simulation of RF PA with wideband signal.

A Patterned SOI LDMOSFET by Masked SIMOX for RF Power Applications

A novel patterned-SOI LDMOSFET with a silicon window beneath the p-type channel was designed and fabricated for RF power amplifier applications. This novel device has good DC and RF characteristics. It has no kink effect on output performance,an off-state breakdown of up to 13V,and fT = 6GHz at DC bias of Vg = Vd = 3.6V.At 1.5GHz,a power-added efficiency （PAE） of 50% is achieved with an output power of up to 27dBm from this device.

A New Two-Branch Amplification Architecture and its Application with Various Modulated Signals

This paper proposes a new two-branch amplification architecture that combines baseband signal decomposition with RF front-end optimization. In the proposed architecture, the filtered modulated signals are separated into two components that are then amplified independently and combined to regenerate an amplified version of the original signal. A branch with an efficient amplifier transmits a low-varying envelope signal that contains the main part of the information. Another branch amplifies the residual portion of the signal. The baseband decomposition and parameters of the RF part are optimized to find the configuration that gives the best power efficiency and linearity. For M-ary quadrature amplitude modulation （M-QAM） signals, this technique is limited in terms of power efficiency. However, for filtered continuous phase modulation （CPM） signals, especially for minimum shift keying （MSK） and Gaussian MSK （GMSK） signals, high power efficiency can be achieved with no significant impact on the overall linearity. The results show that this technique gives better performance than the single-ended ctass-B amplifier.

Higher harmonic voltage analysis of magnetic-alloy cavity for CSNS/RCS upgrade project

Background A rapid cycling synchrotron(RCS)in China Spallation Neutron Source(CSNS)would be upgraded,and the proton beam power will reach 200-500 kW.Three RF cavities loaded by magnetic-alloy(MA)material will be added in RCS tunnel to form a dual-harmonic RF system with eight ferrite-loaded cavities in RCS.The bandwidth of the MA cavity is wide because of its intrinsic Q value of less than 1.Higher harmonics can be excited in MA cavities,because the RF power is directly fed into the MA cavity from the final stage of the RF power amplifier.The distortion of voltage in the cavity gap caused by higher harmonics may deteriorate the beam quality.The influence of the higher harmonics to beam needs to be evaluated and the amplitude of higher harmonics should to be suppressed.Methods We built a mathematical model with two functions based on the RF bucket acceptance and bunch factor to evalu-ate this influence.Groups of harmful amplitudes and phases of higher harmonics were found according to the mathematical model by using multi-objective particle swarm optimization(MOPSO).Conclusion The dual-harmonic RF system with higher harmonics in CSNS/RCS and a suitable harmonic suppression for MA cavities was discussed according to the results of MOPSO and the beam dynamics simulations.