Wye Resistive Splitter

Overview

This is perhaps the simpler combiner/splitter. The Wye splitter provides a N-way equal power split. Since the impedance of the resistor is constant over frequency, this arrangement is very broadband, yet lossy. Care must be taken with high-RF power as the network is dissipative.

Topology

                                  ┌─[R]── Port 1
                                  │
Port_in ──[R]── Node ─────────────┼─[R]── Port 2
                                  │
                                  ├─[R]── Port 3
                                  │
                                  ⋮
                                  │
                                  └─[R]── Port N

Key features:

  • Single input resistor followed by a central star node

  • N identical output resistors, one per output port

  • All ports simultaneously matched to Z₀

  • Inherently lossy: (N−1)/N of the input power is dissipated in the resistors

  • Very broadband, extremely compact

Design Equations (Equal Split)

Resistor Value

R = Z₀ × (N − 1) / (N + 1)

For Z₀ = 50 Ω:

N (outputs)

R (Ω)

Insertion Loss (dB)

2

16.7

6.0

3

25.0

9.5

4

30.0

12.0

8

38.9

18.1

Insertion loss = −10 log₁₀(1/N²) relative to the matched-load case.

References

[1] “Resistive power splitters”, Microwaves101.
https://www.microwaves101.com/encyclopedias/resistive-power-splitters

See Also