An Innovative Lens Type FinLine to Microstrip Transition

Abstract

Due to the disadvantages of vacuum tubes in terms of warm-up time, size, and high-voltage needs, solid-state power amplifiers (SSPAs) with gallium nitride (GaN) monolithic microwave integrated circuits (MMICs) are the key solution for power levels up to some kilowatts in continuous wave. An SSPA is the most convenient solution for these RF power levels due to its low weight, small size, negligible warm-up time, low-voltage operation, and high reliability. Spatial power amplifiers (SPAs) combining techniques are the best candidates for SSPAs due to the intrinsic low attenuation in dividing and combining functions. SPAs mainly use two types of probes: transverse and longitudinal, such as FinLines. This paper describes a broadband FinLine to microstrip (FLuS) transition based on dielectric lens theory. Comparative simulations with traditional FinLine transitions show a significant improvement in matching performances and a very significant increase in mechanical resistance of the transition. The proposed innovative FLuS uses a substrate shaping designed according to dielectric lens theory. Frequency simulations of a FLuS inside the WR22 waveguide are shown. These evidence the better performances of this transition than the classic FLuS transition using quarter-wave transformer (QWT) matching. A Q band spatial power combiner with dielectric lens FLuS was made and measured, showing the excellent performances of this innovative FLuS transition.

Low-loss millimeter-wave resonators with an improved coupling structure

“…Crystalline sapphire is an ideal substrate choice as it yields much lower dissipation than most dielectrics, but is more difficult to machine which imposes design limitations. As a result, transition designs requiring abnormally cut non-rectangular substrates [32][33][34], micromachining [35] or drilled holes [36] are impractical. Sapphire also presents additional challenges for high frequency circuit design due to its relatively high dielectric constant, which leads to more pronounced impedance mismatches caused by the presence of substrate in the waveguide [37].…”

A New Theoretical Approach of Studying Resonances in Single Finline Transitions

“…In Figure 1 is represented the exponential FLuS transition [26][27][28] considered in this paper. The substrate material is Al2O3, with a relative dielectric permittivity ℰ 𝑟 = 9.9.…”

Innovative Mode Enhancement for High Power Coaxial Vircators

“…Considering solid-state devices, recent advances in GaN technology allow us to obtain solid-state high power amplifiers (SSHPAs) at high frequencies and with high reliability [1]. Spatial power amplifiers (SPAs) [2], [3], [4], [5], [6], [7] are the most desired SSHPA-based devices whenever small size, solid-state highpower density, and graceful degradation are needed. The examples of application fields are strategic electronic warfare (EW), electronic counter measurement/electronic counter counter measurements (ECM/ECCMs) systems, and space communications applications.…”