Are you not aware of the fact that radio waves are light that moves at the speed of light?We use radio waves to communicate. They use lights to communicate and scan the area to gain data about the place. We hardily know how to do this with rays. One day we will use light to find and transfer data too. They use light, as it travels faster and can reach other galaxies faster than any other energy or matter we know of.
Great, informative post. Thanks.Alien space faring vehicles in the movies host a myriad assortment of flashing lights of all colors because they are visually pleasing; ditto for the dulcet tones emanating from the mother ship in 'Close Encounters of the Third Kind'.
As for trans-atmospheric travel, all the stalks, antennae and associated masts with their flashing lights on these "space ships" would make such travel 'difficult' to say the least.
A true space faring vehicle, capable of deep space and trans-atmospheric travel, would utilize conformal two dimensional antennae and the ship's skin, like the F-35 Lighting II, would serve as a passive receiver.
One of the central features that makes the F-35 survivable even against high-threat enemies is its ability to suck up electronic signals from radars and air defense nodes, and to quickly classify them, geolocation them, and display them for the aircraft's pilot. This capability makes that traditionally fixed "Blue Line" a flexible one during combat. With F-35 users' mission information being loaded into ALIS then downloaded after every sortie, the electronic intelligence the jet soaks up during its time in the air could be mined and exploited by the U.S.
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The F-35 gathers this info via a series of passive antennas embedded in the F-35's edges that feed signals information to the jet's computers. Using interferometry, the slight time delay between when a signal hits one antenna compared to another, azimuth and range can be defined and target-quality coordinates on where the threatening radio frequency emission is coming from can be devised. This system is known as the F-35's Radar Warning Receiver (RWR) and Electronic Support Measures (ESM) suites. These are tied into a broader set of features that also make up the jet's electronic warfare capabilities.
A group of F-35s can share this information seamlessly via their daisy chain-like directional, low-probability of intercept proprietary Multi-Function Data-Link (MADL). The Electronic Intelligence (ELINT) that the F-35 soaks up allows F-35 pilots to see these "threat rings" in real time and they can choose to avoid, engage, or electronically attack the source of those threat rings depending on where they and their fellow F-35s are located and what their mission is at hand.
What's needed is a flat antenna that is much lighter and easier to accommodate on a mission, while doing the same job as a 3D antenna.
It’s called ‘modulated metasurface’ technology: electromagnetic radiation is influenced not by the curvature of the antenna surface but through careful tailoring of the very surface itself. Thousands of small metal patches of different sizes and orientations are arranged on top of a dielectric layer across the face of the antenna, through which EM radiation is fed through a single central feeding point.
The modulated metasurface antenna patches can be rearranged in such a way to meet nearly any desired focusing, polarisation and direction. While standard antennas are pretty complicated to build, involving a lot of technological processes and skill to achieve the desired curvature and alignments, down to fractions of a millimeter, our antennas are essentially simply printed circuit boards in two dimensions.
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a An incident beam impinging on an STMM is converted into a different frequency harmonic that can be focused at any desired focal point. b Breakdown of Lorentz reciprocity can be shown by probing the time-reversed process. c Photograph of our STMM. d Top view and cross-section of the unit cell. All geometrical parameters are in mm.
All the complexity is shifted from manufacturing to the design side – not so long ago designing these surfaces would have been impossible, because the raw computational power required was not available. There’s a lot of potential for standardisation, and reuse by different missions without the need to requalify the antennas each time – their thermal and mechanical behaviour would be the same, only the layout of elements on the surface would change.
These flat two dimensional antennae, using modulated metasurface technology, are now routinely transmitting data from deep space.
As you can see, flat two dimensional antennae, using modulated metasurface technology, are now seeing greater use. We have come a long way from the long single wire antennae which used stretch from the mast ahead of the cockpits of the Douglas SBD-5 Dauntless dive bombers to the tip of their tails, on those sturdy aircraft which helped us win WWII in the Pacific.
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To dream of man's exploration of the cosmos are the big dreams. I began that trip with James Blish's 'Cities in Flight' tetralogy, which I thought, as a 12 year old, were superb.