Technical data

2-8 Installation and Service Guide N5250-90001
System Description PNA Series Microwave Network Analyzer System
Millimeter-Wave Test Head Modules N5250A
Theory of Operation
Refer to the block diagram in Figure 2-5 on page 2-9 for the following paragraphs.
The N5260A millimeter head controller routes the LO and RF signals from the E8361C PNA to the test set
modules. The millimeter head controller also performs switching from port 1 to port 2. The test head
modules separate the incident from the reflected RF signal and then down convert those signals to an IF
signal
The test head modules do not have their own power supplies; each head receives dc power from the
N5260A millimeter head controller, by way of a multi-pin interface cable.
10 MHz to 67 GHz Operation
The RF signal is received from the E8361C PNA SOURCE OUT and input into the RF IN connector of the
combiner module. The RF signal is then input to either the bias tee or coupler depending on the option
configuration. From the coupler, the RF signal passes through the combiner and then on to the test port.
The signal received at the test port of the combiner (either transmitted from another test head module or
reflected from a device under test) is routed to the RCVR OUT connector via the combiner and coupled arm
of the coupler. This output goes to the E8361C PNA RCVR A IN or RCVR B IN.
67 GHz to 110 GHz Operation
The RF signal is received from the N5260A millimeter head controller and input into the RF IN connector of
the T/R millimeter module. The RF is then amplified and multiplied times six by the source multiplier. This
multiplied incident RF signal then passes through micrometer, attenuator (option), and a dual directional
coupler where a portion of it is coupled off into the reference mixer.
The signal received at the test port of the combiner section (either transmitted from another test head
module or reflected from a device under test) is routed back to the dual directional coupler in the T/R
millimeter module where a portion of it is coupled off into the test mixer.
The LO signal is input from the E8361C PNA LO through the N5260A millimeter head controller. The LO 8th
harmonic is input into the reference and test converters. These converters mix the LO with the RF signals so
that two IF signals are output. These IF signals (incident and reflected) are then output to the millimeter
head controller, as the REF IF and TEST IF signals respectively, and passed to the E8361C PNA for further
processing.