Advances in Power Splitters

Abstract

This article summarizes recent advances in the art of power splitter designs. Diverse design concepts and techniques proposed in recent years are introduced, mainly focusing on the out‐of‐phase power splitters, in‐phase power splitters, filtering power splitters, and high‐power waveguide power splitters. Because of the popularity of balanced circuits, out‐of‐phase power splitters are heavily demanded. The double‐sided parallel‐strip lines (DSPSLs), with the frequency‐independent out‐of‐phase characteristics, are attractive transmission lines for wideband out‐of‐phase power splitter designs. The design methods based on DSPSL for various power splitting responses have been presented, including single‐ and dual‐band, wideband, arbitrary power division ratios. Then, the research on in‐phase power splitters are addressed, focusing on dual‐band operation, arbitrary power division ratios, multiway division, reconfigurable responses, and size miniaturization. The four typical methods for achieving dual‐band operation and five methods for realizing unequal power division ratios are presented. In addition, some techniques for multiway power splitters and reconfigurable power dividers are introduced. As for size reduction techniques, the LTCC and MMIC fabrication processes are introduced and example designs are included. Later, the concept of filtering power splitters is introduced. The power splitters and bandpass filters are combined together to form dual‐function devices with both power splitting and filtering functions. The responses of equal and unequal power division ratios as well as dual‐band operation are presented with the associated design techniques. Finally, coaxial waveguide power splitters are introduced, which are suitable for high‐power millimeter‐wave applications. Various oversized coaxial waveguide structures and probe array arrangement are presented for multioutput applications. Furthermore, some advances on radial waveguide spatial power splitters are addressed and the typical examples are included.

Compact Filtering Rat-Race Hybrid With Wide Stopband

“…1(a), which leads to a large overall component size. It has been found that BPFs can be designed to integrate with the power dividers [15]- [17], power amplifiers [18], and antennas [19] for miniaturization. Similarly, the bandpass filtering function can also be combined with the hybrid, as shown in Fig.…”