NonLin-IM NA-IM1

HHF is world-wide leading in vectorial IM measurements. Our novel product NonLin-IM allows you to perform calibrated complex intermodulation measurements with your VNA. An absolute novelty is the replacement of the comb generator by a new phase reference generator! This novel generators for the commercial frequency bands only reduces the technical effort and the price of the system. Vectorial IM measurements are useful for modelling and IM-source finding. NonLin-IM bases on non-linear multi-port S-parameter using LMR or the novel and patented calibration procedure Without Thru. Without Thru uses only one-port calibration standards (short, open, match, a reference generator and a power sensor) at each port.
The necessary architecture of a modified 3-port network analyzer to measure vectorial IM-products is given in Fig. 1.

Fig. 1: Block diagram of the full measurement set-up for reflection IM measurements with a 3-port VNA with open test-set (e.g. ZVA)

The architecture of a 4-port network analyzer to measure vectorial IM-products is given in Fig. 2.

Fig. 2: Block diagram of the measurement set-up for reflection IM measurements with a 4-port VNA (e.g. ZVB)

4-port network analyzers with only one RF-source are also supported. Fig. 3 shows a very popular test-set to control IM-products at the RX-path of duplexers or switches in RF-frontends by a high TX-signal and a medium antenna signal.

Fig. 3: Block diagram of the measurement set-up for IM measurements at the RX-port with a 4-port VNA (e.g. ENA)

Additionally, the software supports two more IM test sets for transmission measurements. Measurement results exemplify the high quality of the novel vectorial IM measurement system under real-life conditions (Fig. 4a and 4b).

Fig. 4a: Magnitude results of intermodulation measurement
Fig. 4b: Phase results of intermodulation measurement

A novel phase reference generator helps to perform best IM measurements with high accuracy and small frequency step size, Fig. 5.

Fig. 5: Novel phase reference generator with very low phase noise and small step size (here SG 1624 for 1.6 to 2.4 GHz)

Fig. 6 shows a screen shot of the NonLin-IM software.

Fig. 6: NonLin-IM software

This simple measurement system consists of a multi-port-VNA (prefered ZVA from Rohde and Schwarz ), a software, a laptop to control and process one coaxial calibration kit, a power head, and the phase reference generator.


Fig. 7 presents a measurement place of the NonLin-IM system including a simple self-made filter-box. This simple configuration allows a measurement dynamic of 100dB.

Fig. 7: Complete NonLin-IM measurement system

NA-IM1 features in detail:

    • Optimized non-linear multi-port IM test system for vectorial measurements.
    • Accuracy from non-linear calibration procedures LMR for all multi-port VNAs and Without Thru for R&S-VNAs.
    • Special software for intermodulation measurements (supports four IM-test configurations).
    • Supports frequency-, power- and time-sweep IM measurements.
    • Allows the measurement of IM products in an accurate and complex manner.
      • Phase values help to find the location of IM-sources and to generated an accurate non-linear model of your device.
      • The included software module IM finder calculates out of the phase the distance to the IM-source.
    • Fast and easy installation with pre-installed laptop or on your network analyzer.

The use of your own multi-port VNA from Rohde and Schwarz (ZVA, ZVM), calibration kit, and power head helps to reduce the price of entering into the non-linear world.

The measurement performance

    • is based on a small IM-magnitude-error of approximately 0.1-0.2 dB (scalar measurements have errors of 2 dB and more).
    • for the IM-phase is based on a small error of typically 1%.
    • depends from the test-set (selectivity of filters) regarding the measurement time.
    • is depending from the measurement time (typically 2-6 seconds for one measurement sweep).
    • allows to find IM-obstacles with a solution of 1cm (depends on bandwith of the test-set).
    • is based on a VNA which allows to support a typical dynamic of 110dBc plus additional PA.
    • allows the model the IM-obstacles and to characterize the obstables in the different physical phenomenons.

We offer a system composed of

    • Software with dongle and operation manual (necessary),
    • Laptop with LAN-connection (software installed),
    • Coaxial calibration kit (N or 3.5mm) from Rosenberger,
    • VNA from Rohde and Schwarz,
    • Power sensor from Rohde and Schwarz,
    • Calibrated phase reference generator (necessary),
    • Costumer defined IM test sets.

Phase reference generators are for the following frequency ranges available:

    • SG 0615: 600 MHz – 1500 MHz,
    • SG 1024: 1000 MHz – 2400 MHz,
    • SG 1327: 1300 MHz – 2700 MHz,
    • SG 2633: 2550 MHz – 3250 MHz,
    • SG 3135: 3090 MHz – 3500 MHz,
    • SG 3542: 3500 MHz – 4200 MHz.

More details are explained in the operation manual: NonLin-IM_Operating_Manual

More information are available from Info@HHFT.de.