Contents I. Introduction
The demand for ultra-high data rates is driving the evolution of wireless communication. To get higher data rates, it’s required to have high bandwidth with low spectrum congestion, which is available in the low-THz spectrum. the FCC has opened the spectrum between 95 GHz and 3 THz for the development of new applications and services [1]. To use this bandwidth efficiently, higher order modulation schemes are used with a high peak to average power ratio (PAPR), which requires the transmitter PA to have a high PBO efficiency for efficient transmission and that makes the Doherty PA an essential part of modern communication systems. The implementation of the conventional Doherty PA requires transmission line [2], which makes it narrow band and can take a large area on the chip, therefore researchers have been introducing other microwave structures to solve the problems of the section, such as transformers [3], couplers [4], and slot-line based combiners [5]. The power combining of the main PA and auxiliary PA introduces losses from the main PA in the output network of the auxiliary PA. Therefore, we often see a single main and auxiliary PA unit being used. if multiple main and auxiliary PA units are combined, each main PA unit will suffer losses in all the auxiliary networks, resulting in inefficient combining. To solve this issue, this paper presents a power combining technique that allows using a single auxiliary PA with multiple main PA units, and a transformer-based Doherty PA is implemented to demonstrate this technique.
Conventional transformer-based Doherty PA.
