A Transformer-Less Load-Modulated (TLLM) Architecture for Efficient Wideband Power Amplifiers

A Broadband High-Efficiency Doherty Power Amplifier With Integrated Compensating Reactance

“…Therefore, assuming both two amplifiers can achieve output current with the same amplitude over the whole frequency band (i.e., δ=1) and the phase of the peaking amplifier φ equals -θ, the normalized load impedances Z C_low , Z C_sat and Z P_sat can be calculated according to (6), (8) and (9), and the results are illustrated in Fig. 2.…”

“…If the OMN is considered as a lossless reciprocal two-port network, the S parameter matrix of such network can be expressed as [8] …”

“…A transformer-less load-modulated architecture was proposed in [8], which extended the bandwidth by eliminating the use of output impedance transformer and offset lines. The DPA topology based on branch-line couplers has been exploited to achieve up to 36.3% fractional bandwidth [15].…”

High Efficiency Power Amplifiers for Modern Mobile Communications: The Load-Modulation Approach

“…Beyond this, the use of non-conventional output combiners [77][78][79] or the application of the real frequency technique [80] to the design of the output matching networks [75] is proven to be able to further improve DPA bandwidth. In the modified DPA proposed in [46,81], enhancement of DPA bandwidth is obtained by modifying the characteristic impedance Z ∞ of the IIN transformer.…”

Improved Doherty Amplifier Design with Minimum Phase Delay in Output Matching Network for Wideband Application

“…In Fig. 1, because the S parameters of a lossless reciprocal OMN can be determined by two parameters, i.e., S 11 and the phase of S 21 (θ 21 ) [6], the ABCD parameters can also be expressed in terms of S 11 and θ 21 . To design the carrier OMN, the following equations can be obtained:…”