Microstrip Filter Design Tool

Design distributed-element microstrip filters with low-pass or band-pass response, and stubs, stepped impedance or interdigital topology. Select any dielectric substrates, such as PCB or Alumina, and calculate the precise layout dimensions.

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Tool Description

Microstrip Filter Design Tool is a web-based application for distributed-element microstrip filter synthesis. It is feature rich, user-friendly and available for free from any desktop or mobile device.

Note: The design is a first approximation and should be subsequently verified/optimized in a 3D electromagnetic simulation.

Features

  • One-click synthesis from a given specifications
  • Precise layout dimensions on any dielectric substrate
  • Interdigital topology
  • Chebyshev or Butterworth filter types
  • Arbitrary input and output impedances

Contents

1 Lowpass Filters

1.1 Stubs (semi-lumped)

1.1.1 Layout

Stubs (Semi-lumped) Filter Layout

W0 - input and output feed-lines width.

W1 - series lines width.

W2 - stubs width.

Sk - the kth stub length, where the stubs are numbered from left to right starting with 1.

Lk - the kth line length, where the lines are numbered from left to right starting with 1.

1.1.2 Special Parameters

Line Low Impedance (Ω) - the characteristic impedance of the low impedance lines.

Line High Impedance (Ω) - the characteristic impedance of the high impedance lines.

Line Order - control whether the leftmost section is a low impedance line or a high impedance line.

1.2 Stepped Impedance

1.2.1 Layout

Stepped Impedance Filter Layout

W0 - input and output feed-lines width.

W1 - high impedance lines width.

W2 - low impedance lines width.

Lk - the kth line length, where the lines are numbered from left to right starting with 1.

1.2.2 Special Parameters

Line Low Impedance (Ω) - the characteristic impedance of the low impedance lines.

Line High Impedance (Ω) - the characteristic impedance of the high impedance lines.

Line Order - control whether the leftmost section is a low impedance line or a high impedance line.

2 Bandpass Filters

2.1 Interdigital

2.1.1 Layout

Interdigital Filter Layout

W0 - input and output feed-lines width.

W - resonators width.

L - resonators length.

e - the extension in length of the leftmost and rightmost resonators.

t - the input and output feed-lines tapping point.

Sk - the spacing between the kth and (k+1)th resonators, where the resonators are numbered from left to right starting with 1.

2.1.2 Special Parameters

Resonator Impedance (Ω) - the characteristic impedance of the resonators.