X parameters: What are they?

High frequency designers have used S – parameters for a long time when the circuit or device is being characterized in the linear domain. However, once the device or circuit goes beyond the strictly linear domain and enters large signal or nonlinear operating modes a new set of parameters need to be used. A new paradigm is being used now called X parameter analysis, synthesis, measurement and modeling. The Wikipedia description of X parameters is :

“X-parameters represent a new category of nonlinear network parameters for high-frequency design and were developed and introduced by Agilent Technologies as functionality included in N5242A Nonlinear Vector Network Analyzer  and the W2200 Advanced Design System  in 2008. (Nonlinear vector network analyzers are sometimes called large signal network analyzers.)

X-parameters are applicable to both large signal and small signal  conditions, for linear and nonlinear components. They are a mathematical superset of s – parameters meaning that, in the limit of a small signal, Agilent’s X-parameters reduce to S-parameters.

They help overcome a key challenge in RF Engineering, namely that nonlinear impedance differences, harmonic mixing and nonlinear reflection effects occur when components are cascaded under large signal operating conditions. This means that there is a nonlinear and as such non-trivial relationship between the properties of the individual cascaded components and the composite properties of the resulting cascade. This situation is unlike that at DC, where one can simply add the values of resistors connected in series. X-parameters help solve this cascading problem: If the X-parameters of a set of components are measured individually, the X-parameters (and hence the non-linear transfer function) can be calculated of any cascade made from them. Calculations based on X-parameters are usually performed within a harmonic balance* simulator environment.”

X parameters are a useful tool to not only analyze but also to characterize circuits, devices, IC packages or other multiport networks. It is a good tool to learn and know when one works with RF circuits.

* See a tutorial paper on Harmonic Balance Simulation in this blog.

We design and deliver analog and RF/wireless ASICs and modules using state of the art semiconductor, PCB and assembly technologies. Please contact us at spg@signalpro.biz for a quote and a proposal.


SPG designs, develops and delivers custom analog and RF/wireless asics and modules.

FPGA Design and development service

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A wideand RF detector ( 40 Mhz to 3 Ghz) -75 dBm to 5 dBm input

A wideband RF detector

A wideband RF detector

Linear detector performance

Linear detector performance curves

A wideband linear RF detector

Price for one unit: $25.00. Lead time for delivery 3 days. 30 Day return policy. Pricing for 100 units or more: $20.00 per unit.  Please contact Signal Processing Group Inc. for details for purchase from Signal Processing Group Inc. Email: spg@signalpro.biz 24/7

Wideband RF detector perforamce , more details

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2 stage 35 dB gain RF amplifier. Front of the module

Full range frequency response

2 stage amplifier deta

Please see details at http://www.signalpro.biz/2rf_amplifier_details.htm    Delivery lead time is 3 days. Return within 30 days for a full refund. Price is $15.00 for one unit and $10.00 per unit in volumes of 100. For higher volumes than 100 please contact Signal Processing group Inc.

miniature LNA module

Mni LNA performance

Delivery lead time is 3 days. Return within 30 days for a full refund. Price is $15.00 for one unit and $12.00 per unit in volumes of 100. For higher volumes than 100 please contact Signal Processing Group Inc. at email: spg@signalpro.biz or call 602-626-0272 for fastest service.

A high frequency divider from 500 Mhz to % Ghz+

The input interface.
The frequency divider has a differential analog interface. The following parameters apply:
The minimum frequency that can be input is 500 Mhz and the maximum frequency is 6.0 Ghz.
The RF input level is 5 dBm to – 5 dBm. For lower frequencies make sure that the slew rate is
greater than 560 V/us. The input is biased by two 500 Ohm resistors connected to a 1.6V DC bias.
Therefore AC coupling is used at the input. These are two 100pF capacitors.
The output interface.
The output is single ended. The output driver is capable of sourcing and sinking 24 mA. The
equivalent output impedance is 50 Ohm. To avoid reflections it is recommended that the divider
work into a 50 Ohm load.
General operation.
The inputs are applied to the input SMA I/O. The product will work with both a differential input as
well as a single ended input. However, a differential input works best. The division ratio is applied
to the N1 and N2 control inputs as follows:
N2 N1 Division ratio
0 0 8
0 1 16
1 0 32
1 1 64
The logic levels are:
Logic level Voltage
1 1.4V minimum
0 0.6V maximum
The supply voltage interface.
The operating supply voltage is 3.3V typical. The quiescent (DC) operating supply current is 2 mA.

A high frequency divider 500 Mhz to 5 Ghz+

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SPDT DC to 3 Ghz RF switch

DC to 3 Ghz RF SPDT switch

RF Switch typical features

Supply voltage = Vcc = 0/+5 Vdc
Operatng temperature = TA = -50° C to 125 Deg C
Operating impedance = 50 Ohm
Input power for 1 dB
compression ( 5.0V system) = 37 dBm ( f = 0.5 to 3 Ghz)
Input third order Intercept = 64 dBm ( 0 to 5.0V system, f = 0.5 to 3 Ghz)
Operating frequency range = DC to 3 Ghz.
Insertion loss DC to 3 Ghz = 0.8 dB
Isolation DC to 3 Ghz = 14 dB minimum
Return loss DC to 3 Ghz = 20 dB
50% contl to 10/90 %
( ON/OFF) = 120 ns

A single stage RF amplifier as a gain block

A single stage RF amplifier summary specifications

Summary Specifications

Gain,  Operating: 19.5 dB
Operating frequency range: 1.0 – 2700 Mhz
OIP3: (Pout = 19.0 dBm),  -8.5 dBm
P1dB: 4.6 dBm
N.F: 4.2 dB
Supply voltage Operating: 3.3  – 5.5 Volts

Price: single unit $7.50, 100 units : $5:50.

Free delivery, shipping lead time 2 days.

30 day return policy, buyer ships.
Supply current Supply = 5.0V,  23.0 mA

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