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MixerIMT2 (Intermodulation Table Mixer)


Available in ADS

Name Description Units Default
ConvGain Conversion gain multiplier from RF port (Port 1) to IF port (Port 2) None dbpolar(0,0)
SP11 RF port reflection coefficient None polar(0,0)
SP12 IF port to RF port leakage coefficient None polar(0,0)
SP13 LO port to RF port leakage coefficient None polar(0,0)
SP21 RF port to IF port transmission/leakage †† coefficient None polar(0,0)
SP22 IF port reflection coefficient None polar(0,180)
SP23 LO port to IF port transmission/leakage †† coefficient None polar(0,0)
SP31 RF port to LO port leakage coefficient None polar(0,0)
SP32 IF port to LO port leakage coefficient None polar(0,0)
SP33 LO port reflection coefficient None 0
NF Input double side band noise figure; must be a non-negative real number dB None
NFmin Minimum double sideband noise figure at Sopt; must be a positive real number dB None
Sopt Optimum Source Reflection for Minimum Noise Figure, use x + j × y, polar(x,y), dbpolar(x,y) for complex value None None
Rn Equivalent noise resistance; must be a non-negative real number    
R1 Reference impedance for RF port; must be a non-negative real number    
R2 Reference impedance for IF port; must be a non-negative real number    
R3 Reference impedance for LO port; must be a non-negative real number    
M_RF ††† IMT order for RF port None 15
N_LO ††† IMT order for LO port None 15
IMTValueType IMT value type: enumerated as {dB, dBm} None dB
IMT_File File containing intermodulation table; accepted formats MDIF: IMT, P2D, S2D None imtfile.imt

These parameters can be reported in any of the following complex number formats: x + j × y, polar(x,y), dbpolar(x,y), vswrpolar(x,y)

†† Transmission/leakage implies that the value of this parameter is used as an additive supplement to gain expressions between RF->IF and LO->IF ports.

††† Must be set to a value less than or equal to the number of harmonics represented in the IMT table. The limit on the number of rows and columns in an IMT table is 15.

  1. For new designs, this component should be used only if MixIMT_Data does not provide necessary functionality.
  2. To use NFmin , Sopt , and Rn to characterize noise, the following condition must be satisfied for a realistic model:

    If the noise parameters attempt to describe a system that requires negative noise (due to Rn being too small), the negative part of the noise will be set to 0 and a warning message will be issued.
  3. Use the function polar(mag,ang), or dbpolar(dB,ang), or vswrpolar(VSWR,ang) to convert these specifications into a complex number.
  4. For an S-parameter or a noise figure sinusoidal ripple, use the function ripple (mag, intercept, period, variable); for example ripple(0-1, 0-1, 10 MHz, Freq).
    Example: S21=dbpolar(10+ripple( ),0.)
  5. MixerIMT2 accepts only O-type IMT files where only single RF on single LO mixing can be specified with implicit assumption about reference RF and LO frequencies. These files are inherently single side banded descriptions of mixer behavior and do not contain IF phase information. For details on various IMT file formats see Working with Data Files > IMT Format.
  6. When supplied a signal at frequency Freq_Signal at the RF port and a local oscillator frequency Freq_LO at the LO port, MixerIMT2 produces intermodulation products at all frequencies
    |m × Freq_LO +/- n × Freq_Signal|
    -M_RF ≤ m ≤ M_RF and -N_LOn ≤ -N_LO
    The simulation controller may be set to compute fewer frequency components than shown in the above equation. As a general rule, the values of _M_RF_ and _N_LO_ should be set to the order(s) of RF and LO tones on the simulator component and these values must be less than or equal to the number of rows and columns of the IMT table. The largest IMT table supported by this component is of size 16 × 16.
    If there are multiple frequencies at the RF and LO ports, there will be a superposition of the RF-LO intermodulation tones. For example, given the frequencies LO1 and LO2 at the LO port, and Signal1 and Signal2 at the RF port, there will be intermodulation products at the frequencies:
    |m × Freq_LO1 +/- n × Freq_Signal1|,
    |m × Freq_LO1 +/- n × Freq_Signal2|,
    |m × Freq_LO2 +/- n × Freq_Signal1|,
    |m × Freq_LO2 +/- n × Freq_Signal2|
    -M_RF ≤ m ≤ M_RF and -N_LOn ≤ _N_LO
    Note that there will be no products at | LO 1 +/- LO 2|, | Signal 1 +/- Signal 2| and other RF or LO self-modulation products at the output of the mixer.
  7. MixerIMT2 can be used in all simulations except for Frequency Converting AC analysis.
  8. MixerIMT2 leakage terms are specified in two separate ways: the IMT file entries, and the SPij parameters. For example, LO to IF leakage is given by the (M=1, N=0) term in the IMT file as well as the SP23 parameter. When both specifications are given, the total leakage is given by the complex sum of the two specifications. It is generally advisable to leave SP23=SP13=0; in this case, the LO to IF and the RF to IF leakages are specified by the IMT file.
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