Distributed Components >Chapter 2: Microstrip Components
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MCFIL (Microstrip Coupled-Line Filter Section)

Available in     ADS and RFDE

Subst = microstrip substrate name

W = line width, in specified units

S = spacing between lines, in specified units

L = line length, in specified units

Temp = physical temperature, in °C

W1 = (ADS Layout option) width of line that connects to pin 1

W2 = (ADS Layout option) width of line that connects to pin 2

Range of Usage

Simulation frequency    (GHz)


Er = dielectric constant (from associated Subst)
H = substrate thickness (from associated Subst)
W 0, S 0, L 0    for layout
W1 0, W2 0

  1. The frequency-domain analytical model is a distributed, coupled-line model. The per-unit-length coupling capacitances are calculated using the formula developed by Kirschning and Jansen for parallel coupled microstrip lines, and the formula developed by Hammerstad and Jensen for single microstrip line. Dispersion, end effect, and conductor loss are included. The even- and odd-mode line impedances are calculated based on the coupling capacitances and conductor losses. The result is used to calculate the network parameters of the distributed, coupled-line model.

  2. For time-domain analysis, an impulse response obtained from the frequency-domain analytical model is used.

  3. To turn off noise contribution, set Temp to -273.15°C.

  4. In generating a layout, adjacent transmission lines will be lined up with the inner edges of the conductor strips. If the connecting transmission lines are narrower than the coupled lines, they will be centered on the conductor strips.


[1] R. Garg and I. J. Bahl. "Characteristics of Coupled Microstriplines," MTT-27, July 1979.

[2] M. Kirschning and R. H. Jansen. "Accurate Wide-Range Design Equations for the Frequency-Dependent Characteristic of Parallel Coupled Microstrip Lines," MTT-32, January 1984 (with corrections by Agilent).

[3] E. Hammerstad and O. Jensen. "Accurate Models for Microstrip Computer-Aided Design," MTT Symposium Digest, 1980, pp. 407-409