Millimeter Wave Radiated Harmonic Emissions Testing Kit

OML is pleased to present a radiated harmonic and spurious emissions testing kit designed to fulfill the spirit of the FCC required testing(1) for radiating devices (transmitters) operating between 23 and 78 GHz. The kit consists of the appropriate waveguide mixers and horn antennas(2) as listed below. The mixers are typically equivalent in performance to Tektronix WM780/490 series mixers. External diplexers are not needed for use with: Advantest 3271/72, Anritsu 2667C/2702/2802/710 and Rhode & Schwarz. FSEx/FSIQ/FSM. External diplexers are required and are available for use with: HP/Agilent 70000/856x and IFR/Marconi 9xx/18xx/2393. Tektronix # 015-0385-00 external diplexer is required for use with Tektronix 279x/275x/49x series analyzers. Typical delivery is 90 days ARO. These products are subject to U.S. Gov’t. Export Regulations and Licensing.(4)

In 1998, the FCC adopted the terminology of “certification” in its Part 15 rules with regard to “licensed” and “unlicensed” transmitters. As part of that action and with subsequent actions, the FCC has redefined the spurious emissions suppression requirements for certification (type acceptance). Currently, the manufacturer must test for and certify that the output spectrum of his transmitter product meets the relevant FCC criteria as to radiated levels for all spurious emissions, including harmonics. It appears that it is concern over the potential interference that could be caused by these harmonic emissions that is the root cause for these requirements. In general, these are the current spurious emissions testing requirements:

Operating frequency, equipment under test	Frequency range to be investigated
below 10 GHz	to the lower of the 10th harmonic or 40 GHz
10 to 30 GHz	to the lower of the 5th harmonic or 100 GHz
above 30 GHz	to the lower of the 5th harmonic or 200 GHz
76 to 77 GHz	to 231 GHz

The FCC specifies spurious emission limits in a radiated signal environment, in some form of watts or volts per square meter. This measurement is usually accomplished by using a harmonic mixer,(3) fitted with a horn antenna of known gain, with some type of field strength measurement receiver such as a spectrum analyzer, all of which make up the “receiver system.” Testing for spurious emissions should be accomplished with the transmitter under test signal being radiated and its radiated spectrum being examined using the receiver system. The measured results, in power, are then converted to field strength, i.e., dBuv/m2, dBm/m2, etc.

The OML Harmonic Testing Kit contains mixers and horn antennas that will allow continuous coverage of 40 to 220 GHz when used with an appropriate spectrum analyzer. The kit includes mixer/antenna combinations for the following waveguide bands: 40 to 60 GHz, 60 to 90 GHz, 90 to 140 GHz and 140 to 220 GHz. As an option, a mixer/antenna for the 220 to 325 GHz band is available. The mixer/antennas are available for the individual bands. These specific frequency bands were chosen not only to achieve continuous coverage but to also make beneficial use of the waveguide frequency cutoff characteristics of each band. This waveguide cutoff characteristic acts as a highpass filter blocking lower harmonics, that could be interpreted as unfavorable false spurious indications, from entering the mixers. A mixer should not be used out of band. Not only would the mixer not be operating properly, but it is possible that a harmonic could be generated in the mixer itself. An example would be to use a 18 to 26 GHz mixer to measure the 48 GHz 2nd harmonic of a 24 GHz transmitter. A chart illustrating the harmonic relationships and the appropriate mixer to be used for each is an attachment to this document.

The 40 to 60 GHz and the 60 to 90 GHz mixers are supplied with measured conversion loss data taken with the OML mixer conversion loss test set.(3) The 90 to 140 GHz and 140 to 220 GHz mixer are tested for proper operation. They can not be measured for conversion loss because of the lack of any recognized power standard for those bands.

Many spectrum analyzers have built-in L.O./I.F. diplexers. However, some major brands do not and an external diplexer is required. OML has external diplexer designs available for most all applications. Please inquire.

1) There are no recognized power standards above 96 GHz on which to base this requirement.

2) The horn antennas included above are rectangular horns mathematically designed for 24 dB gain (no data).

3) For detailed specifications and OML test procedures see:“OML Millimeter Wave Single Diode Unbalance Harmonic Mixers” data sheet, the “OML Millimeter Wave Harmonic Mixer Test Set” description, the OML “Test Procedure for Single Diode Harmonic Mixers”, and the OML millimeter wave spectrum analysis application note.

4) International and Export buyers contact: Radar Systems Technology, 650 949 8041 Fax 650 949 8082

300 Digital Drive, · Morgan Hill, CA 95037
Tel. (408) 779-2698 · FAX: (408) 778-0491 · email: info@omlinc.com