A Quad-Band Doherty Power Amplifier Based on T-Section Coupled Lines

Abstract

This letter proposes a new design technique for quad-band Doherty power amplifier (DPA) based on the T-section coupled lines network (TCLN). The TCLN allows for the design of a quad-band impedance inverter at three arbitrary frequencies and one associated frequency offering more flexibility in the design of quad-band DPAs than the state of the art. The ratio of the largest operating frequency to the smallest operating frequency is found in the range 1.95 to 7, as the ratio of the other two operating frequencies is located in the range of 1.3 to 2.76. A quad-band DPA is implemented with TCLN, operating at 0.73, 1.65, 2.67, and 3.57GHz. The measured results agree with the anticipation perfectly.

Automated design for a hybrid lumped and distributed dual‐band stub using aggressive space mapping

“…Compared with the traditional DBSs presented in References , the presented DBS in this paper is realized in a purely planar layout without loading any SMDs or etching defected ground structures, and therefore it presents lower insertion loss at the dual bands and features ease fabrication. Besides, ad hoc optimization techniques were not provided for conventional planar DBSs . Except in Reference , a two‐step ASM technique was applied to synthesize the CATL based DBS, but it was not fully automated since a relatively complex procedure had to be went through beforehand to determine the implementable range for each optimizable variable.…”

“…The nonresonant‐type and the resonant‐type CRLH ATLs both belong to the dispersion engineering realm, where the dispersive phase shift and the Bloch impedance characteristics of the ATLs can be regulated to develop multi‐band devices . Another mainstream design idea is the network equivalence, requiring that the network parameters of the MBS equal to those of the uniform TL . Analytical formulae for a Π‐shaped dual‐band stub (DBS) were deduced by equalizing its transfer function matrix to that of a uniform 90° TL .…”

“…Two‐section C‐type coupled line can realize a dual‐band Chebyshev impedance transformer or a quad‐frequency impedance transformer, respectively . A T‐section coupled lines network was utilized as a quad‐band impedance transformer to design a quad‐band Doherty power amplifier . Two T‐shaped DBSs are cascaded to construct 180° dual‐band phase shifter, integrated in an improved 3 dB dual‐band directional coupler .…”

“…[1][2][3][4][5][6][7] Another mainstream design idea is the network equivalence, requiring that the network parameters of the MBS equal to those of the uniform TL. [8][9][10][11][12] Analytical formulae for a Π-shaped dual-band stub (DBS) were deduced by equalizing its transfer function matrix to that of a uniform 90 TL. 8 Two-section C-type coupled line can realize a dual-band Chebyshev impedance transformer or a quadfrequency impedance transformer, respectively.…”

“…9,10 A T-section coupled lines network was utilized as a quad-band impedance transformer to design a quad-band Doherty power amplifier. 11 Two T-shaped DBSs are cascaded to construct 180 dual-band phase shifter, integrated in an improved 3 dB dual-band directional coupler. 12 Overall, dispersion engineering and network equivalence are the two major design concepts for building up MBSs.…”