The Very Old Glossary of Generic RF Devices

50-Ohm Load

This is a simple 50Ω resistive load, which can also be accessed by the keyboard shortcut Alt+5.

Attenuator: Pi-Type

This is a four-pin, two-port device that models a resistive power attenuator with the "Pi" configuration. The characteristic impedances of the input and output transmission lines can be different. The K-parameter is the power attenuation ratio from the input to the output.

Model Identifier: attenuator Pi Bold text

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
Zo1	input line characteristic impedance	Ohms	50.0
Zo2	output line characteristic impedance	Ohms	50.0
K	input/output power ratio	-	1.0

Attenuator: T-Type

This is a four-pin, two-port device that models a resistive power attenuator with the "T" configuration. The characteristic impedances of the input and output transmission lines can be different. The K-parameter is the power attenuation ratio from the input to the output.

Model Identifier: attenuator T

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
Zo1	input line characteristic impedance	Ohms	50.0
Zo2	output line characteristic impedance	Ohms	50.0
K	input/output power ratio	-	1.0

Bias Tee

This is a six-pin, three-port device that models a passive RF bias tee. The two RF and DC inputs mix into the output (RF+DC) port.

Model Identifier: bias-tee

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
L	inductance	nH	100.0
C	capacitance	nF	100.0

Branchline Hybrid Coupler

This is an eight-pin, four-port device that models a branchline quadrature hybrid coupler. If Port 1 acts as an input port, the output power is equally split between Ports 2 and 3. Port 2 has 90° phase shift with respect to the input, while Port 3 is in-phase with respect to the input. Port 4 acts as an isolated port. Since the branchline hybrid has a symmetric structure, any port can serve as the input port. You have to specify the center frequency of the device in GHz.

Model Identifier: branchline

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
Z0	line characteristic impedance	Ohms	50.0
eeff	effective permittivity	-	1.0
fc	center frequency	GHz	1.0
len	port line segment length	mm	10.0

Complex Impedance

This is a two-pin, one-port device that models a generic impedance with both real and imaginary parts. It can be used in place of a one-port device when input impedance data are available rather than s11-parameter values.

Model Identifier: impedance

Parameters:

A table of z11-parameter values as a function of frequency

Generic Bend Junction

This is a four-pin, two-port device that models a bend in a general purpose transmission line. The bend geometry and the line structure can be very complicated, and their full-wave effects can be captured by the measured or simulated S-parameter data of this device. The model may also include a certain length of the transmission line at the input and output ports.

Model Identifier: bend-junction

Parameters:

A table of s11, s21, s12 and s22-parameter values as a function of frequency

Generic Coupled T-Lines

This is an eight-pin, four-port device that models a two parallel general purpose coupled transmission line segments. Ports 1 and 2 represent the input and output of the first T-Line. Ports 3 and 4 represent the input and output of the second coupled T-Line.

Model Identifier: coupled-lines

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
Z0e	even mode characteristic impedance	Ohms	50.0
Z0o	odd mode characteristic impedance	Ohms	10.0
eeff	effective permittivity	-	1.0
len	line segment length	mm	10.0

Generic Cross Junction

This is an eight-pin, four-port device that models a cross junction among four general purpose transmission lines. The cross geometry and the line structures can be very complicated, and their full-wave effects can be captured by the measured or simulated S-parameter data of this device. The model may also include a certain length of the four transmission lines at the four ports.

Model Identifier: tee-junction

Parameters:

A table of s11, s21, s31, s41, s12, s22, s32, s42, s13, s23, s33, s43, s14, s24, s34 and s44-parameter values as a function of frequency

Generic Multiport Networks

RF.Spice A/D currently offers four types of generic network devices: one-port, two-port, three-port and four-port. There are two-pin, four-pin, six-pin and eight-pin, respectively. Multiport networks can be used to model very complicated active or passive structures, which can be characterized by their measured or simulated S-parameter data.

Model Identifier: one-port, two-port, three-port, four-port

Parameters:

One-Port: A table of s11-parameter values as a function of frequency

Two-Port: A table of s11, s21, s12 and s22-parameter values as a function of frequency

Three-Port: A table of s11, s21, s31, s12, s22, s32, s13, s23 and s33-parameter values as a function of frequency

Four-Port: A table of s11, s21, s31, s41, s12, s22, s32, s42, s13, s23, s33, s43, s14, s24, s34 and s44-parameter values as a function of frequency

Generic Open End

This is a two-pin, one-port device that models the open end of a general purpose transmission line segment. Infringing capacitance effects can be captured by the measured or simulated S-parameter data of this device. The model may also include a certain length of the transmission line.

Model Identifier: open-end

Parameters:

A table of s11-parameter values as a function of frequency

Generic Open Stub

This is a two-pin, one-port device that models a general purpose transmission line segment terminated in an open end. An infinite impedance load is indeed connected to the end of the T-line segment. The fringing capacitance effects, however, are neglected by this model.

Model Identifier: stub-open

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
Z0	characteristic impedance	Ohms	50.0
eeff	effective permittivity	-	1.0
alpha	attenuation constant	dB/m	0.0
len	line segment length	mm	10.0

Generic Short Stub

This is a two-pin, one-port device that models a general purpose transmission line segment terminated in a shorted end. A zero impedance load is indeed connected to the end of the T-line segment. The inductive loading effects, however, are neglected by this model.

Model Identifier: stub-short

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
Z0	characteristic impedance	Ohms	50.0
eeff	effective permittivity	-	1.0
alpha	attenuation constant	dB/m	0.0
len	line segment length	mm	10.0

Generic Step Junction

This is a four-pin, two-port device that models a step-in-width junction between two general purpose transmission lines. The step geometry and the line structures can be very complicated, and their full-wave effects can be captured by the measured or simulated S-parameter data of this device. The model may also include a certain length of the two transmission lines at the input and output ports.

Model Identifier: step-junction

Parameters:

A table of s11, s21, s12 and s22-parameter values as a function of frequency

Generic T-Line

This is a four-pin, two-port device that models a general purpose transmission line segment.

Model Identifier: t-line

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
Z0	characteristic impedance	Ohms	50.0
eeff	effective permittivity	-	1.0
alpha	attenuation constant	dB/m	0.0
len	line segment length	mm	10.0

Generic Tee Junction

This is a six-pin, three-port device that models a tee junction among three general purpose transmission lines. The tee geometry and the line structures can be very complicated, and their full-wave effects can be captured by the measured or simulated S-parameter data of this device. The model may also include a certain length of the three transmission lines at the two through ports and the side arm.

Model Identifier: tee-junction

Parameters:

A table of s11, s21, s31, s12, s22, s32, s13, s23 and s33-parameter values as a function of frequency

Ideal Circulator

This is a six-pin, three-port device that models an ideal microwave circulator. There are two types of this device: Clockwise Circulator and Counterclockwise Circulator . The ideal circulator model is a simple non-reciprocal 3×3 scattering matrix fixed over all frequencies.

Model Identifier: circulator_cw & circulator_ccw

Parameters: None

Quarter-Wave Impedance Transformer

This is a four-pin, two-port device that models a quarter-wave impedance transformer. You have to specify the center frequency of the device in GHz.

Model Identifier: impedance transformer

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
Zo1	input line characteristic impedance	Ohms	50.0
Zo2	output line characteristic impedance	Ohms	50.0
eeff	effective permittivity	-	1.0
fc	center frequency	GHz	1.0
len_in	input line segment length	mm	10.0
len_out	output line segment length	mm	10.0

Rat-Race Hybrid Coupler

This is an eight-pin, four-port device that models a rat-race hybrid coupler. You have to specify the center frequency of the device in GHz. A rat-race coupler can be operated in a number of different modes:

• If Port 1 is used as the input port, the power will be equally split into two in-phase components at Ports 2 and 3, and Port 4 will be isolated.

• If Port 4 is used as the input port, the power will be equally split into two components with a 180° phase difference at Ports 2 and 3, and Port 1 will be isolated.

• Combiner Mode: Ports 2 and 3 act as two input ports. Then, the sum of the two inputs will form at Port 1, while their different will form at Port 4.

Model Identifier: rat-race

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
Z0	line characteristic impedance	Ohms	50.0
eeff	effective permittivity	-	1.0
fc	center frequency	GHz	1.0
len	port line segment length	mm	10.0

Resistive Power Divider

This is a six-pin, three-port device that models a resistive power divider with equal output powers at Ports 2 and 3. This power divider has wideband operation.

Model Identifier: resistive power divider

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
Z0	line characteristic impedance	Ohms	50.0
eeff	effective permittivity	-	1.0
len_in	input line segment length	mm	10.0
len_out	output line segment length	mm	10.0

Wilkinson Power Divider

This is a six-pin, three-port device that models a Wilkinson power divider with unequal output power split at Ports 2 and 3. You have to specify the center frequency of the device in GHz. It is very important to note that if the Power Ratio K is different than one, then the two output Ports 2 and 3 of the power divider must be terminated in load impedances equal to Z₀ . √K and Z₀ / √K, respectively.

Model Identifier: wilkinson

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
Z0	line characteristic impedance	Ohms	50.0
eeff	effective permittivity	-	1.0
fc	center frequency	GHz	1.0
K	ratio of power of Port 3 to power of Port 2	-	1.0
len_in	input line segment length	mm	10.0
len_out	output line segment length	mm	10.0

 

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