Slot Line Conversion Calculator

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The Slot Line Conversion Calculator computes the effective dielectric constant (εeff) and guide wavelength (λg) for a slot line based on the operating frequency and substrate dielectric constant. It helps engineers analyze signal propagation characteristics and design high-frequency planar circuits with accurate wavelength control.

Formula

εeff = (εr + 1) / 2

λg = λo / √(εeff)

where λo = c / f and c = 3 × 108 m/s

Formula Explanation

  • εr = Relative dielectric constant of the substrate.
  • εeff = Effective dielectric constant representing the propagation medium for the slot line mode.
  • λo = Wavelength in free space determined by the frequency.
  • λg = Guide wavelength, which indicates how the signal travels within the slot line.

Uses of this calculator

  • Designing and analyzing microwave slot line components.
  • Determining wavelength shortening effects due to the substrate.
  • Optimizing slot line filters, couplers, and antennas.
  • Evaluating dielectric effects in hybrid and monolithic RF circuits.

What is the guide wavelength for a 10 GHz slot line on a substrate with εr = 4.4?

Input: f = 10 GHz, εr = 4.4

Output:

  • εeff = (4.4 + 1) / 2 = 2.7
  • λo = 3 × 108 / 10 × 109 = 0.03 m
  • λg = 0.03 / √2.7 = 0.03 / 1.643 = 0.0183 m
  • Guide wavelength (λg) ≈ 18.3 mm