The design of a hexagonal six-ridged waveguide (H6RWG) phased array antenna (PAA) element featuring a wide scan angle matched slotted horn aperture is presented for Ka-band satellite downlink in low Earth orbit non-terrestrial network applications. The proposed PAA element is evaluated against an open-ended waveguide (OEWG) PAA element and achieves a very low active reflection coefficient (ARC) of less than -18 dB and a total antenna efficiency greater than 84% over a wide bandwidth from 17.3 to 20.2 GHz with a $\pm$ 50$^\circ$ scan range. Specifically, the aperture of the H6RWG was designed to limit the variations in ARC during scanning, thereby minimizing load pulling of integrated active devices, as demonstrated with a power amplifier (PA) in a co-simulation. As a result, the power-added efficiency, output power, and linearity of the PA remained stable over the bandwidth and scan range. Compared to the OEWG PAA, the co-polarized system efficiency and equivalent isotropic radiated power are improved for most scan angles within the bandwidth, especially at high scan angles.

This paper presents the characterization and modeling process of MASMOS structures by means of a classical compact three-port electrical non-linear model approach. From DC and S-parameters measurements, a large signal model (LSM) has been developed for two different MASMOS structures. The proposed LSM and associated modeling approach have been validated through load pull measurements with different harmonic load conditions. Then, generic multi-tone measurements have been carried out making use of an innovative test bench to quantify linearity performances of MASMOS structures. The model is used in a power amplifiers design flow for LTE applications and is expected to allow a significant reduction of simulation time, compared with technological-oriented model as BSIM3.