filterCombline

Create combline filter in microstrip form

Since R2022b

Description

Use the filterCombline object to create a combline filter in the microstrip form.

Creation

Syntax

filter = filterCombline

filter = filterCombline(Name=Value)

Description

filter = filterCombline creates a default combline line filter using an Alumina substrate with the passband of the filter centered around 3.1 GHz.

filter = filterCombline(Name=Value) sets Properties using one or more name-value arguments. For example, filterCombline(ResonatorWidth=0.0016) creates a combline filter with a resonator width of 0.0016 meters. Properties not specified retain their original values.

Properties

FilterOrder — Order of filter

3 (default) | positive scalar

Order of the filter, specified as a positive scalar.

Example: filter = filterCombline(FilterOrder=4)

Data Types: double

ResonatorLength — Length of resonator

0.0030 (default) | positive scalar | vector

Length of the resonator in meters, specified as a positive scalar or a vector of positive elements equal in size to FilterOrder.

Example: filter = filterCombline(ResonatorLength=0.007)

Data Types: double

ResonatorWidth — Width of resonator

0.0016 (default) | positive scalar

Width of the resonator in meters, specified as a positive scalar.

Example: filter = filterCombline(ResonatorWidth=0.0017)

Data Types: double

ResonatorSpacing — Spacing between resonators

4e-04 (default) | positive scalar | vector

Spacing between the resonators in meters, specified as a positive scalar or a vector of positive elements equal in size to (FilterOrder-1).

Example: filter = filterCombline(ResonatorSpacing=0.0008)

Data Types: double

ResonatorOffset — Y-offset of each resonator

0 (default) | positive scalar | vector

Y-offset for each resonator in meters, specified as a positive scalar or a vector of positive elements equal in size to FilterOrder. If the value is a scalar, all the resonators have the same offset along the Y-axis.

Example: filter = filterCombline(ResonatorOffset=(0 0.1 0.2))

Data Types: double

PortLineLength — Length of input and output lines

0.0011 (default) | positive scalar

Length of the input and output lines in meters, specified as a positive scalar.

Example: filter = filterCombline(PortLineLength=0.0014)

Data Types: double

PortLineWidth — Width of input and output lines

0.0013 (default) | positive scalar

Width of the input and output lines in meters, specified as a positive scalar.

Example: filter = filterCombline(PortLineWidth=0.0087)

Data Types: double

FeedOffset — Y-offset for input and output lines

3e-04 (default) | positive scalar

Y-offset for the input and output lines in meters, specified as a positive scalar.

Example: filter = filterCombline(FeedOffset=0.0087)

Data Types: double

Capacitor — Capacitor value

1e-12 (default) | positive scalar

Capacitor value in farad, specified as a positive scalar.

Example: filter = filterCombline(Capacitor=2e-12)

Data Types: double

Height — Height of combline filter from ground plane

0.0012 (default) | positive scalar

Height of the combline filter from the ground plane in meters, specified as a positive scalar. For multilayer dielectrics, use the Height property to create the filter between the two dielectric layers.

Example: filter = filterCombline(Height=0.0028)

Data Types: double

GroundPlaneWidth — Width of ground plane

0.0050 (default) | positive scalar

Width of the ground plane in meters, specified as a positive scalar.

Example: filter = filterCombline(GroundPlaneWidth=0.0048)

Data Types: double

Substrate — Type of dielectric material

dielectric object

Type of dielectric material used as a substrate, specified as a dielectric object. The dielectric material in a filterCombline object with default properties is Alumina.

Example: d = dielectric("FR4"); filter = filterCombline(Substrate=d)

Conductor — Type of metal used in conducting layers

metal object

Type of metal used in the conducting layers, specified as a metal object. The type of metal in a filterCombline object with default properties is PEC.

Example: m = metal("Copper"); filter = filterCombline(Conductor=m)

Object Functions

charge	Calculate and plot charge distribution
current	Calculate and plot current distribution
design	Design coupled line filter around specified frequency
feedCurrent	Calculate current at feed port
getZ0	Calculate characteristic impedance of transmission line
layout	Plot all metal layers and board shape
mesh	Change and view mesh properties of metal or dielectric in PCB component
shapes	Extract all metal layer shapes of PCB component
show	Display PCB component structure or PCB shape
sparameters	Calculate S-parameters for RF PCB objects

Examples

Default Combline Filter

Create a default combline filter.

filter = filterCombline

filter = 
  filterCombline with properties:

         FilterOrder: 3
     ResonatorLength: 0.0030
      ResonatorWidth: 0.0016
    ResonatorSpacing: 4.0000e-04
     ResonatorOffset: 0
      PortLineLength: 0.0011
       PortLineWidth: 0.0013
          FeedOffset: 3.0000e-04
           Capacitor: 1.0000e-12
              Height: 0.0012
    GroundPlaneWidth: 0.0050
           Substrate: [1x1 dielectric]
           Conductor: [1x1 metal]

View the filter.

show(filter)

Zero-Offset Feed Combline Filter

Create a combline filter with the feed offset equal to zero.

filter = filterCombline('FeedOffset',0);

Visualize the filter.

show(filter);

Third-Order Combline Filter with Resonator Offset

Create a third-order combline filter with a different resonator offset.

filter = filterCombline(FilterOrder=3,ResonatorLength=[0.005,0.002,0.007],...
    ResonatorSpacing=[0.6e-3,1.2e-3],ResonatorOffset=[0.001e-3,0,0.5e-3], ...
    GroundPlaneWidth=12e-3);

Visualize the filter.

show(filter);

References

[1] Pozar, David M. Microwave Engineering. 4th ed. Hoboken, NJ: Wiley, 2012.

[2] Al-Yasir, Y., R.A. Abd-Alhameed, J.M. Noras, A.M. Abdulkhaleq, and N.O. Parchin. “Design of Very Compact Combline Band-Pass Filter for 5G Applications.” In Loughborough Antennas & Propagation Conference 2018 (LAPC 2018), 61 (4 pp.)-61 (4 pp.). Loughborough, UK: Institution of Engineering and Technology, 2018

[3] Hong, Jia-Sheng. "Microstrip Filters for RF/Microwave Applications". 2nd ed. Wiley Series in Microwave and Optical Engineering. Hoboken, N.J: Wiley, 2011.

Version History

Introduced in R2022b