Microstrip Open End

A microstrip open-circuit termination with end-effect modeling.

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=20e-3)
ms_open = MicrostripOpen("MO1", substrate=sub, w=3.0e-3)
gnd = Ground("GND")

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

# Connect line with open end
@connect circ port1.nplus ms_line.n1
@connect circ ms_line.n2 ms_open.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("Open-ended stub S11 at ", freq[1]/1e9, " GHz: ", round(abs(s11[1]), digits=3))

Open-ended stub S11 at 1.0 GHz: 0.984