Text preview for : 5991-3776EN Achieving Accurate E-band Power Measurement with Keysight E8486A Waveguide Power Sensors part of Agilent 5991-3776EN Achieving Accurate E-band Power Measurement with Keysight E8486A Waveguide Power Sensors Agilent 5991-3776EN Achieving Accurate E-band Power Measurement with Keysight E8486A Waveguide Power Sensors c20140829 [7].pdf
Back to : 5991-3776EN Achieving Acc | Home
Keysight Technologies
Achieving Accurate E-band Power
Measurements with E8486A
Waveguide Power Sensors
Application Note
Introduction
The 60 to 90 GHz spectrum, or E-band, has been gaining more
millimeter wave (mm-wave) application interest in the recent
years. There are a few reasons for this. The E-band has no or
little license governance for frequency bands of 60 GHz, and
70 to 80 GHz. These spectrums have wider usable bandwidth
and are hence able to handle super high speed communication
transmissions. E-band products also require smaller antennas,
Figure 1. Waveguide to coaxial adaptors
making the overall product designs and packaging more
interesting--as well as challenging. Among the applications
for E-band are high-speed mobile backhaul, point-to-point radio
communication, automotive radar for collision avoidance and car
safety, and the 802.11ad or WiGig communication standard.
In most cases, the E-band mm-wave devices or modules in the
applications mentioned above have either a WR-12 waveguide
or 1-mm coaxial connector, particularly on the output path of
the transmitter or power amplifier. For high-power mm-wave
applications, waveguides are commonly used since they provide
better transmission with low loss and good shielding. When
measuring the RF power from these devices using power meters
and sensors, the connectors on the power sensors must be
selected correctly in order to reduce the mismatch measurement
uncertainty.
For example, if a device under test (DUT) has a WR-12 connector
test port, using a direct termination of WR-12 connector power
sensor is preferred. However, frequently the measurement is
obtained using a power sensor that has something other than
a WR-12 connector (such as a WR-10 or WR-15 connector, or
a 1-mm coaxial) and an adaptor or taper must be used. This
configuration increases the mismatch measurement uncertainty
(shown in Figure 1).
Using mm-wave power measurement application examples, this
paper illustrates the flexibility of using the Keysight Technologies,
Inc. E8486A waveguide power sensor with a WR-12 test port to
obtain more reliable and accurate measurements.
E-band mobile backhaul transceiver power measurement
With the increasing demand for ultra-high data rates for LTE Advanced and
other emerging wireless technologies, mobile backhaul has been moving into
the E-band spectrum in recent years. The point-to-point (P2P) communication
link in E-band handles the high data capacity requirement and has fewer
licensing restrictions. Figure 2 shows a P2P transceiver module which is
typically mounted on top of high rise buildings or antenna structures.
Figure 2. P2P transceiver modules (photography
One of the transceiver module's key measurement parameters is the output provided courtesy of Sub10)
power. The output power measurement can be directly measured using the
E8486A waveguide power sensor as shown in Figure 3. Near-perfect matching
of the WR-12 connection between the transmitter out test port and the power
sensor enables accurate power measurement. The maximum standing wave
ratio (SWR) of the E8486A is guaranteed not to exceed 1.08. The E8486A power
sensor also is compatible with all the Keysight RF power meters such as the
N1911/12/13/14A, E4416/17A, E4418/18B, and some legacy models. With a
wider dynamic range, E8486A with Option 200 goes down to