How to implement SWaP-C satcom antenna arrays using SMD power dividers and directional couplers Written by Steven Keeping
The space around the Earth is filling fast, and thousands more new satellites are due for launch in the next decade. That’s putting pressure on satellite communications (satcoms) designers from two sides. First, available bandwidth for satcoms in the traditional L, C and X bands is fast being used up. Secondly, commercial satellite builders want their products to be lighter and cheaper to launch. Satcom designers are responding to the lack of RF bandwidth by moving communications from the traditional satellite bands to higher frequency RF bands such as Ku (12 to 18 gigahertz (GHz)). The Ku band offers the potential for greater throughput and is much less congested. With respect to the demand for minimal size, weight,
satellite, such as the antenna array, using advanced packaged surface mount devices (SMDs). This article outlines the benefits of SMD power dividers and directional couplers, key passive elements used in Ku band satcom antenna arrays. The article introduces example devices from Knowles Dielectric Labs, describes how these components meet today’s low-SWaP demands, and how designers can use key performance characteristics of these vital components to optimize antenna array performance.
which essentially perform as mini antenna. The benefits of antenna arrays compared to a conventional antenna for satcoms applications include: ■ Higher gain ■ Increased signal-to-noise ratio (SNR) ■ Steerable transmission beams and enhanced sensitivity to incoming signals from a particular direction ■ Better diversity reception (helps overcome signal fading) ■ Smaller side lobes in the antenna radiation pattern The conventional array structure comprises a 3D-brick configuration made up of electronic assemblies placed side-by-side and attached using multiple connectors and cables. This increases the bulk and complexity of an antenna array, compared with single-antenna dishes.
Advances in antenna arrays
Recent developments in satellite and ground station antennas have seen a move away from single-antenna dishes to antenna arrays. Antenna arrays combine two or more elements, each of
power, and cost (“SWaP-C”), designers are responding by building key elements of the
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