Control scheme of harmonics and third‐order intermodulation distortion with composite right/left‐handed structure for linearity enhancement of power amplifier module

Abstract

In this article, in order to enhance the linearity of power amplifier modules (PAM), we have suppressed the harmonics at the output port of a high-power amplifier (HPA) and cancelled the thirdorder intermodulation distortion (third IMD) by a predistortion scheme. The matching network to suppress the harmonics consists of metamaterial like the composite right/left-handed structure. Both the second and third harmonics are suppressed over 27 dBc. A phase of generated third IMD at the output of the drive amplifier has changed in order to offset the third IMD of HPA. The harmonics of the proposed PAM suppresses over 6 dB more than a single HPA and over 20 dB more than a reference power amplifier. The PAM has 37 dBm of output power and 21.6 dB of power gain. The second harmonic and third IMD are À53 and À42.5 dBc about PAM, respectively.ABSTRACT: A methodology to design high-power amplifiers composed of several amplifier blocks and passive combiners/dividers is proposed. The optimum matching condition between amplifiers and combiners has been found using the mixed-mode S-parameters approach. Measurements and computer-aided design simulations have been successfully used to validate the proposed approach. V C 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1500-1504, 2013; View this article online at wileyonlinelibrary.com.

Intermodulation in nonlinear SQUID metamaterials: Experiment and theory

“…To analyze the dynamics, we expressδ as an in-phase part and a quadrature part, i.e.δ = δ R + iδ I , and write the real and imaginary parts of Eq. (8). We note that in the absence of losses (Q → ∞) one can construct a Hamiltonian function for the nonlinear system.…”

“…Nonlinearity is a key consideration in a wide range of important applications including amplifiers [1][2][3] and tunable filters [4]. Introduction of nonlinearity into metamaterials facilitates tunability, design flexibility, and self-induced nonlinear responses [5,6], giving rise to developments in metamaterial-based amplifiers [7,8] , filters [9][10][11] and antennas [12][13][14]. However, as data streams containing multi-frequency signals pass through these nonlinear components, they generate intermodulation (IM) products via frequency mixing [15].…”