The mystery of the "Bandpass Radome"

[untitled]

Negative. We retain our anti-gravity modules, our warp engines, and photon torpedoes, for our military only!

You forgot hyperspace drive

 

[Bratva]

Negative. We retain our anti-gravity modules, our warp engines, and photon torpedoes, for our military only!

That's why Most Aliens like to visit America and not any other country

 

[DANGER-ZONE]

the description says its 6 foot long and the seller is selling it for 1300 dollars.
can be bought to find out what materials are used.
Jet nose cone F-22 Jet fighter | eBay

Looks like it is made from fiberglass... did they say if it were from the original plane or not?

Fiber glass is one of the most important material used to make Nose Cone. Radar rays can easily pass through Fiber glass. while the other radar cannot detect its surface from outside.

see below, A PAF Mirage 3 Wreckage at a PAF bone-yard. Fiberglass threads are visible (Save and zoom it for largeer view), hanging out of damaged cone surface. you can also figure it out how much amount of Fiberglass is used in this cone. probably 70 - 80 %.

 

[Bratva]

Can Whole aircraft be made of fiber glass?

 

[Safriz]

Can Whole aircraft be made of fiber glass?

that will expose the engine...wirings and other parts to radar and will be even worse for stealth.

 

[nightcrawler]

All,

Instead of "radome bandpass" or the likes, I recommend 'ansoft frequency selective surfaces' for your word search. Slide 20 is applicable to the construction of a radome, especially the 'stealth' version. A basic layman understanding of FSS is the start for this topic.

So a white cloth-like layer with thousands of diamond structures that is pasted infront of my microwave oven glass door is an example of FSS?...avoid egress of microwaves

 

[Chogy]

So a white cloth-like layer with thousands of diamond structures that is pasted infront of my microwave oven glass door is an example of FSS?...avoid egress of microwaves

In a way, YES. The screen selectively allows EM radiation of a particular frequency (light) to pass through, and blocks microwave frequency EM radiation.

What you are seeing is the holes at work. The size of the holes is SMALLER than the wavelength of the microwave energy, but LARGER than the wavelength of light. The light waves sneak right through.

 

[Safriz]

^^same cannot be done for a frequency hopping radar.

 

[Chogy]

^^same cannot be done for a frequency hopping radar.

And that is why the whole thing is a high-tech mystery!

 

[Jango]

And that is why the whole thing is a high-tech mystery!

To which who knows the answer?

 

[gambit]

So a white cloth-like layer with thousands of diamond structures that is pasted infront of my microwave oven glass door is an example of FSS?...avoid egress of microwaves

In a way, YES. The screen selectively allows EM radiation of a particular frequency (light) to pass through, and blocks microwave frequency EM radiation.

What you are seeing is the holes at work. The size of the holes is SMALLER than the wavelength of the microwave energy, but LARGER than the wavelength of light. The light waves sneak right through.

The above illustration may not be to scale as am not an 'artist' but all one has to do is resize the image so that any wave matches an actual metric ruler. Remember, the X-band is centimetric and the HF/VHF/UHF bands are metric.

Radar - Wikipedia, the free encyclopedia

HF 3–30 MHz 10–100 m
X 8–12 GHz 2.5–3.75 cm

The 'visible' wavelengths are in the 'nm' range.

Light - Wikipedia, the free encyclopedia

Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz.

So compared to visible wavelengths, it is not that difficult to block centimetric radar signals. Or to selectively pass through some wavelengths.

 

[Chogy]

A quick web search says a typical microwave oven is 2.45 gigahertz, the larger wave that Gambit illustrated. I'm surprised it is that long.

 

[nightcrawler]

A quick web search says a typical microwave oven is 2.45 gigahertz, the larger wave that Gambit illustrated. I'm surprised it is that long.

simple calculation

f= frequency in Hz
c= speed of light 3E8 or 300000000 in m/s
λ = wavelength in m

now say for 3Ghz = 3E9 HZ
c= 3E8 m/s
now putting these values in parent formula you get 0.1m for λ = 10cm

same applies for all other frequencies
next time do calculate & tell us what is the λ value you come up with L-band (not mentioned by Gambit)

 

[Thomas]

And that is why the whole thing is a high-tech mystery!

I would research left handed meta materials. Their use in military radars is becoming the standard (at least in the west). Plently of information through goggle available.

 

[Safriz]

I would research left handed meta materials. Their use in military radars is becoming the standard (at least in the west). Plently of information through goggle available.

I didnt know about this..Nice share and wicked....
Tunable metamaterials - Wikipedia, the free encyclopedia

Looks very plausable in F-22 Radome construction....But i have a reservation.
Raptor was built mainly between 1997-2005..But the meta materials you suggest are still in experimental stage with few practical uses....

Cant there be a simpler system at work inside the radome? such as microwave polarization?
www.dtic.mil/dtic/tr/fulltext/u2/a445264.pdf
Here is a 7 page scholarly article about selective polarization on radar waves which serves as anti jamming measure by estimating the polarization of enemy radar waves and filtering them by changing the orientation of polarization filter..for example if the enemy radar wave is found to be polarized in x plane the own radar will transmit Y plane polarized Radar waves and all radar energy polarized in any other plane will be blocked from reaching the radar scanner..

So if an AESA radar hops Polarity in addition to the frequency ..it will not only be impossible to Jam..It will be stealth too...
The only addition will be an existing mature technology of may be Liquid crystal polarizer film inside the radome which by induction of electric current changes polarity matching it with transmitting polarization of radar antenna.
Mathematically it will be highly improbable that enemy radar and own radar will ever be transmitting and receiving at same frequency and polarity...
So effectively its not the frequency the F-22 raptor's radome is blocking its the polarity which its blocking....
When iy transmits in say Y plane polarized radar waves..thge polarization filter will only allow Y plane polarized radar waves to enter the radome..The it will shift to X axis polarized radar waves on any frequency and the Filter will only allow X axis polarized radar waves..and so on..
In my opinion such a system will be much simpler to construct..
why iam not in favour of Frequency blocking inside the Raptor radome as it will be very complex...keeping in mind that the exact frequency of returning radar waves are unknown due to Doppler shift..Moving targets will reflect radar waves at different frequency that the original transmitted frequency? So precisely filtering radar frequencies will be nightmare..While filtering Polarizations will be practical and easier?

What says you?