10-2019

RF & Wireless
Complex Microwave Feed
Assembly
Broadband, Multistage
GaN-on-Si Power Amplifier
Module
Link Microtek has designed and fabricated
a complex microwave feed
assembly for use in a customer’s Kuband
mobile satellite-communications
antenna system. Widely used around
the world by news crews, first responders,
government agencies and military
units, such mobile antenna systems provide
a durable and quickly deployable
solution for anyone requiring reliable
satellite communications facilities in
remote locations.
The Link Microtek assembly incorporates
a feed arm, transmit and receive
filters, a rotary joint and an orthomode
transducer (OMT). In addition to satisfying
the tight space constraints imposed
by the compact nature of the antenna
system, the feed assembly had to achieve
strict performance criteria regarding low
transmission losses and cross polarisation,
as well as high isolation between
transmit and receive channels. The feed
arm is formed of WR75 waveguide to
handle the Ku-band frequency ranges
of 13.75 to 14.5 GHz for transmit and
12 to 13 GHz for receive. This is linked
via a length of semi-rigid waveguide to
a transmit filter, which bends round to
interface to the rotary joint – the purpose
of which is to accommodate one of
the degrees of movement as the foldaway
satcom system unfurls once in situ.
The simple external appearance of the
rotary joint masks the complexity of its
internal design, which consists of over
40 separate precision-engineered parts,
including connectors, pins, cages, spring
mounts and bearings. On the other side
of the rotary joint is the OMT. The
function of this device is to separate
the transmit and receive signals, and in
conjunction with the receive filter the
OMT achieves an impressive isolation
figure of over 100 dB.
■ Link Microtek Ltd
www.linkmicrotek.com
Richardson RFPD, Inc. announced the availability
and full design support capabilities
for a new 10 W hybrid GaN module from
Macom Technology Solutions Inc. The
MAMG-100227-010 is a broadband, twostage
GaN-on-Si hybrid power amplifier
module in an air-cavity laminate package.
The 10 W device is fully-matched and covers
wide 225...2600 MHz frequency range. A
gold-plated copper heat sink is attached to
the bottom side of the laminate substrate.
The package can be accessed from the top
or the bottom allowing for “live bug” or
“dead bug” mounting. This mounting flexibility
enables streamlined designs for smaller,
lighter radios. The new module is ideal
for use in tactical military communications,
LMR, and wireless (public safety) markets.
Additional key features of the MAMG-
100227-010 include:
• Fully-matched at input and output
• 28 V operation (typ.); 36 V (max)
• CW output power >10 W
• 40% PAE
• 22 dB power gain
• Compact size: 14 x 18 mm
■ Richardson RFPD
www.richardsonrfpd.com
100 W Power Limiter with
Adjustable Threshold
RFMW announced design and sales support
for a 10 MHz to 6 GHz RF power limiter
capable of handling 100 W of pulsed input
power. The pSemi PE45361 is a monolithic
structure up to 8 times smaller than discrete,
PIN-diode solutions and eliminates thermal
hysteresis.
The adjustable input, 1 dB compression point
(limiting threshold) is set from 7 to 13 dBm
via a low current control voltage, eliminating
the need for external bias components
such as DC blocking capacitors, RF choke
inductors and bias resistors. Fast response
time of