Stripline Impedance Calculator

What is Stripline Impedance? 

In a stripline, the transmission line configuration is such that there is a flat conductive trace between two ground planes, with a certain dielectric material in between. The characteristic impedance characterizes the impedance existing along the length of the stripline and is relied on for signal integrity, especially within high-frequency circuits. Appropriately doing the impedance matching will make sure there will be a minimum signal reflection but a maximum power transfer. 

The stripline configuration is excellently shielded and, therefore, often preferred in RF circuits where impedance needs to be controlled tightly and EMI reduced. Good impedance control can help design microwave components such as filters, couplers, and antenna feed networks. 

The calculator simplifies the calculation for this impedance of stripline structures, enabling designers to optimize circuit performance without sacrificing signal quality. 

Inputs: 

• Trace Width (W): The width of the copper trace, in mils. 
• Trace Thickness (T): The thickness of the copper trace, in mils. 
• Substrate Height (H): The height of the dielectric material separating the trace from the ground plane, in mils. 
• Dielectric Constant (ϵr): The relative permittivity of the dielectric material. 

Calculation: 

The characteristic impedance of a stripline, denoted by Z0, is calculated using the following empirical formula: 

Where: 

• Z₀  = Characteristic impedance (Ω) 
• W = Trace width (mils) 
• T = Trace thickness (mils) 
• H = Substrate height (mils) 
• ϵ_r  = Dielectric constant of the substrate 

Outputs: 

• Impedance (Z₀): The calculated characteristic impedance of the stripline, in ohms (Ω).