Microstrip Via

A microstrip via hole connecting to the ground plane.

using CircuitSim

circ = Circuit()

# Substrate definition
sub = Substrate("Sub1", er=4.5, h=1.6e-3, t=35e-6)
add_component!(circ, sub)

# Components
port1 = ACPowerSource("P1", port_num=1, impedance=50.0)
ms_line = MicrostripLine("MS1", substrate=sub, w=3.0e-3, l=10e-3)
via = MicrostripVia("VIA1", substrate=sub, d=0.3e-3)
gnd = Ground("GND")

add_component!(circ, port1)
add_component!(circ, ms_line)
add_component!(circ, via)
add_component!(circ, gnd)

# Connect line with via to ground
@connect circ port1.nplus ms_line.n1
@connect circ ms_line.n2 via.n1
@connect circ port1.nminus gnd

# S-parameter analysis
sp_analysis = SParameterAnalysis(start=1e9, stop=10e9, points=50, z0=50.0)
result = simulate_qucsator(circ, sp_analysis)

freq = result.frequencies_Hz
s11 = result.s_matrix[(1,1)]
println("Via grounded stub S11 at ", freq[1]/1e9, " GHz: ", round(abs(s11[1]), digits=3))

WARNING: Model for microstrip via hole defined for freq/C0*h < 0.03 (is 0.030367)
WARNING: Model for microstrip via hole defined for freq/C0*h < 0.03 (is 0.031828)
WARNING: Model for microstrip via hole defined for freq/C0*h < 0.03 (is 0.0333594)
WARNING: Model for microstrip via hole defined for freq/C0*h < 0.03 (is 0.0349644)
WARNING: Model for microstrip via hole defined for freq/C0*h < 0.03 (is 0.0366466)
WARNING: Model for microstrip via hole defined for freq/C0*h < 0.03 (is 0.0384098)
WARNING: Model for microstrip via hole defined for freq/C0*h < 0.03 (is 0.0402578)
WARNING: Model for microstrip via hole defined for freq/C0*h < 0.03 (is 0.0421948)
WARNING: Model for microstrip via hole defined for freq/C0*h < 0.03 (is 0.0442249)
WARNING: Model for microstrip via hole defined for freq/C0*h < 0.03 (is 0.0463527)
WARNING: Model for microstrip via hole defined for freq/C0*h < 0.03 (is 0.0485828)
WARNING: Model for microstrip via hole defined for freq/C0*h < 0.03 (is 0.0509203)
WARNING: Model for microstrip via hole defined for freq/C0*h < 0.03 (is 0.0533703)
Via grounded stub S11 at 1.0 GHz: 0.991