Hybrids and directional couplers

Overview

Four-port board components: a power split with a 90° or 180° phase shift and couplers with a set coupling, for arrays, balanced amplifiers and measurements.

From the simplest to the most complex: a 3 dB branch-line with 1 section, up to a two-section bridge, a 180° rat-race, 10 and 20 dB couplers with a shield and four connectors.

Typical performance

• Port VSWR < 1.3 over the design band, isolation ≥ 18–25 dBtypical
• Band: a 1-section branch-line ≈ 10–20 %, a rat-race ≈ 20–30 %typical
• Amplitude balance ± 0.3–1 dB, phase ± 1–3° over the bandtypical

Typical values describe the antenna class, not a guarantee for a unit; “computed” marks our own simulated example.