RF Circuit Synthesis Tools

Introduction

The data management panel contains a tab with tools for synthesizing RF some passive RF circuits:

• Filters

• Matching networks

• Power combining/splitting circuits

• Attenuators

RF synthesis tools widget

Design Tools

Filter Design

The following RF and MW filters can be synthesized:

Topology	Respose type	Notes
Lumped LC filters
- Canonical filters	LPF / HPF / BPF / BSF
- Elliptic	LPF / HPF / BPF / BSF
- Direct-coupled (BPF)	BPF
Stepped-Z	LPF
Quarter-wavelength	BPF / BSF
Capacitively-coupled shunt resonators	BPF
Side-coupled	BPF
End-coupled	BPF
Semilumped	LPF/HPF

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Matching Networks

Single-port and two-port matching networks can be synthesized. The load can be entered manually or loaded from a Touchstone file.The following topologies are available:

Topology	Elements	Bandwidth	Complex Loads	Adjustable
L-section	2 lumped	Narrow (5-10%)	Yes	No
Single-stub	1 TL + stub	Moderate (10-20%)	Yes	No
Double-stub	1 TL + 2 stubs	Moderate (10-20%)	Yes	Yes
Multisection λ/4	N×λ/4 TL	Broad (40-80%)	Real only	No
Cascaded LC	2N lumped	Moderate (20-40%)	Real only	No
λ/8 + λ/4	2 TL sections	Moderate (10-20%)	Yes	No

Power combining

This tool allows to synthesize a number of power splitters/combiners and couplers

Topology	Outputs	Power Split	Isolation	Bandwidth	Notes
Wilkinson	2	Equal/Unequal	Excellent	Medium	Most common, simple
Multistage Wilkinson	2ⁿ	Equal	Excellent	Wide	Cascaded 2-way stages
T-Junction	2	Equal/Unequal	None	Narrowband	Simplest, reactive
Branch-line	2	Equal/Unequal	Good	Medium	90° phase, quadrature hybrid
Double-box Branchline	2	Equal/Unequal	Better	Medium	Improved branch-line
Bagley	N	Equal	Good	Narrowband	Multi-way, planar
Gysel	2	Equal	Excellent	Medium	High power, grounded resistors
Lim-Eom	2	Equal	Excellent	Wide	Wideband improvement
3-way Improved Isolation	3	Equal	Excellent	Medium	Enhanced 3-port isolation
Recombinant 3-way Wilkinson	3	Equal	Excellent	Medium	Alternative 3-port design

Attenuator design

Topology	Notes
Pi	Matched
Tee	Matched
Bridged-Tee	Matched
Reflection attenuator	Matched
Quarter-wavelength series	Frequency-dependent. Output port unmatched
Quarter-wavelength shunt	Frequency-dependent. Output port unmatched
L-pad 1st series	Very broadband matching
L-pad 1st shunt	Very broadband matching
Series resistor	Two ports unmatched
Shunt resistor	Two ports unmatched

Matching Network Design

Topology	Elements	Bandwidth	Complex Loads	Adjustable
L-section	2 lumped	Narrow (5-10%)	Yes*	No
Single-stub	1 TL + stub	Moderate (10-20%)	Yes	No
Double-stub	1 TL + 2 stubs	Moderate (10-20%)	Yes	Yes
Multisection λ/4	N×λ/4 TL	Broad (40-80%)	Real only	No
Cascaded LC	2N lumped	Moderate (20-40%)	Real only	No
λ/8 + λ/4	2 TL sections	Moderate (10-20%)	Yes	No

See Also

• RF Engineering Calculators