E5052B Signal Source Analyzerand E5053A Microwave Downconverter

Extension of a two-channel cross-correlation technique to  mmW signals

Recent development of several advanced communications and sensing systems in millimeter-waves (mmW) requires that you accurately evaluate mmW signal quality. Among many characteristics or operation parameters, the phase noise or jitter of a signal source is becoming particularly important for achieving reliable system performance.

In addition to aerospace and defense applications, many commercial and popular applications of mmW such as 60 GHz band wireless Personal Area Network (IEEE-802.15.3c), 76.5/79 GHz band automotive radar sensors and 90 GHz band radio-metering, low-cost solutions for testing lower phase noise (jitter) signal sources are needed more than ever before.

The advantage of a two-channel cross correlation technique in phase noise measurements is that you can extend to mmW (up to 110 GHz). Using the E5052B signal source analyzer (up to 7 GHz), the E5053A microwave downconverter (up to 26.5 GHz), two

external harmonic mixers, and a power splitter will offer low phase noise measurement capability along with the mmW

software application equipped in the E5052B.

The simplest test configuration for cross-correlation technique is shown in Figure 1

Once the harmonic mixer and target frequency are setup, the E5052B can automatically select local oscillator (LO) frequencies. The optimum setting of input attenuation and IF amplifier gain can be done manually in order to get the lowest phase noise.

Figure 2 and Figure 3 are an example of a 76.5 GHz phase noise measurement setup with Keysight 11970W mixers. Figure 4 shows phase noise floor (sensitivity limit) of the setup with a single correlation. This indicates E5052B’s excellent sensitivity even in mmW, for example –130 dBc/Hz at 1 MHz offset frequency for 77 GHz carrier.

Figure 5 illustrates actual phase noise and amplitude noise mea­surement results of 76.5 GHz. It is important to understand the noise characteristics of the signal source under test, the E5052B can display both phase and amplitude noise traces on the same scale. (Note that “power level” shown is not calibrated due to conversion-loss uncertainty of a power splitter and harmonic mixers.) The E5052B is able to measure phase and amplitude noise components without any reconnection of mmW waveguide. Measurement time is merely less than 3.5 seconds in this case.

The E5052B and the E5053A provides a simple but very sensitive and fast solution for mmW phase noise characterization and evaluation.