No abstract

The hybrid integration of an additively fabricated air-filled waveguide (WG) with a printed circuit board (PCB) is presented. An arrangement is proposed where different waveguiding structures share the same common metal plane on PCB. Such an approach allows combining the low-loss and high-Q properties of an air-filled waveguide, active circuit realization of the strip transmission line, and 3-D capabilities of additive manufacturing. A broadband transition is developed employing a through-patch coupling interface from a microstrip (MS) line to a waveguide. The concept was experimentally validated with exemplary transitions operating within X-band and K -band, featuring a measured bandwidth of f h / f l ≈ 1.4 and average pertransition loss including connecting lines of ∼1.2 and ∼1.9 dB, respectively.

A Class-S Amplifier architecture theoretically Modulator IDriverand lPowerswitchesl Balun offers high efficiency and nonlinearity resistance. Classlevel shifter and filter S idea is assumed to base on ideal switches which work in two states -ON and OFF, and these conditions enable I-+> t nonlinearity resistance. Real implementations are based on

A novel modulation concept based on ∆-Σ modulation dedicated for a Class-S Amplifier based on GaN technology is presented. This paper includes system considerations of efficient modulation schemes for GaN switching transistors, which suffer from many limits. The analyses are focused on evaluating the impact of modulation scheme on the switching conditions of the transistors. Moreover practical figures of merits are introduced for defining optimum modulation strategy. Simulations are performed for a carrier frequency of 890.88 MHz for UMTS 5 MHz bandwidth signal. Results describe the main differences and limits of modulation schemes dedicated for switching mode power amplifiers.

2El e n a . Se r e b rya kova @ Tu -I l me na u . d e Abstract-A Class-S Power Amplifier architecture theoretically offers high efficiency operation and seems to be an attractive alternative for classical PAs architecture. Switching mode PA principle assumes operation on digital, single -bit Delta-Sigma (b.~) modulated signals which contain significant level of outof-band noise. As a result, switching concept requires very narrowband, low loss filter solution which can handle with high power signals. Complexity of Class-S idea and operation on different types of signals require definitions of new analyze and test procedures which are valid for switching mode PAs. Presented work describes spectral measurement tests for b.m odulated signals and output reconstruction filter. Moreover work defines filter requirements for output of the 3 types of modulation based on b.~scheme which can be engaged in Class-SPA. Analyses and measurements were performed at the carrier frequency of 450 MHz.