Simulating Impedance Values
Characteristic impedance
In this equation, h is the thickness of the insulating layer, W is the line width of the conductor, t is the thickness of the conductor, and εr is the dielectric constant of the insulator.
(Source: The Printed Circuit Handbook)
The parameters determining the impedance of a microstrip line are as follows:
- 1.Pattern width
- 2.Insulation layer thickness
- 3.Dielectric Constant
- 4.Conductor thickness (plating thickness)
In particular, the first and second of these items have a major impact in determining the impedance value. At Elna, impedance calculations are performed using the S-6000C characteristic impedance calculation software by Polar Corp., where the impedance can be approximated using the thickness of the insulation layer and the width of the circuits.
Measuring the Impedance Values
- 1.Unit Product Name
Agilent Technology Company Measurement Instrument 86100C/54754A is used - 2.Measurement Methods
After the equipment is calibrated, the tip of the probe described above is placed on the respective test coupons for each layer (two points for each layer, including the ground) to make a connection, at which time the measurements are made.
- Shape of test coupon:
The shape of the test coupon is subject to change.
