TLMatch (Tapered-Line Match)

Symbol

Parameters

Name	Description	Unit	Default
Subst	Microstrip substrate name	None	MSub1
F	Design frequency	GHz	1
Zo	Desired input impedance	Ohm	50
Rload	Load impedance to match	Ohm	100
ResponseType	Type of frequency response (exponential, triangular, Klopfenstein)	None	Exponential
L	Length of tapered line in wavelengths at frequency F (set L=0 to compute L)	None	0.0
Rmax	Maximum voltage reflection coefficient	None	0.1
NSection	Number of linear taper sections per wavelength	None	20

Notes

1. A tapered-line matching network matches a real load impedance (Rload) to a desired real input impedance (Zo) using a continuously varying line characteristic impedance to realize a specified frequency response. The reflection coefficient remains below the specified maximum value for all frequencies above the design frequency.
2. The continuous impedance taper of this circuit is approximated using a sequence of linear tapers. Increasing the number of sections per wavelength (NSection) will improve the approximation to the defined taper.
3. If the length of the line L is set to zero, the Design Assistant chooses L such that the reflection coefficient is less than Rmax for all frequencies above the design frequency. Otherwise, Rmax is ignored.
4. The ResponseType specifies the distribution of the impedance along the length of the line and therefore determines the frequency response of the match.
5. No Optimization Assistant is provided since the design process is exact to within the approximation of the continuous impedance taper using multiple linear taper segments. Increasing the value of NSection will improve the computed response.
6. A SmartComponent subnetwork is empty until the Design Assistant is used to generate the design. Refer to Design Assistant.

For a more detailed discussion of this device, see: D. M. Pozar, Microwave Engineering, 2nd Edition, John Wiley & Sons: New York, 1998, pp. 288-295.

Example

A tapered-line matching network was designed to match a load impedance of 100 Ohms to a 50 Ohms line at a center frequency of 4 GHz. Specifying a Klopfenstein frequency response for which the reflection coefficient remains below 0.1 along with 30 sections per wavelength dictates 18 tapered-line sections to realize the match. The plot has been shown in linear magnitude rather than dB to emphasize the equal-ripple frequency response.