Contacting Nokia and Finding an Antenna Designer

1.

Irving Campus

6000 Connection Drive
Irving, TX 75039
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Mountain View Campus

380 N.
Bernardo Ave.
Mountain View, CA 94043
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Redmond Campus

5000 148th Ave NE Suite 150
Redmond, WA 98052
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2. Contact a consulting engineering company, or a head hunter.

That is an amazing link. Thanks!

I didnn't see frequency mentioned. There is a big difference between VLF and microwave.

You are correct, sorry about that:

918 - 928 MHz

Note:

Frequency of antenna: 918 - 928 MHz

You are better off performing a search on the internet for antenna design information and teaching yourself.

There are good books available too but you will need to pay for them, still plenty of free antenna design information on the internet to start you on your way (including antenna designs). We are assuming there is a good reason for not buying an existing inexpensive antenna.

What's the application?

Hey there,

I'm trying to design an antenna/antenna-array that can project a signal in all directions (to at least 20 ft) of 3-D space from a 59 mm (x-axis) x 124mm (y axis) x 1mm(z axis) open box (open on one x-y plane side). Power available is up to 1 mW.

This is getting tedious.

What is this "box"? Plastic, metal, tin foil, glass?

Is there anything else in this imaginary box?

What does all directions really mean?

I think this is a waste of time.

So your trying to design a thin element omnidirectional antenna to fit into a specific area.

Not really possible (as mentioned below) but do you know the sensitivity figures for the receiver at a distance of 20 feet?

Based on my limited experience the 900MHz antenna length will be longer than the available y-axis length but you may be able to alter the shape to fit the space at the cost of losing uniform omnidirectionalability (signal strength will vary depending on receiver position). That's why sensitivity figures will be crucial as to if the antenna will work with the intended receivers. Quite a lot after thinking about it, it will be very directional with an available depth of only 1mm, if it is even possible to fit it all in.

http://en.wikipedia.org/wiki/Electrical_length

I am NOT an antenna designer by trade but if memory serves me there are free design programs available on the internet that will allow you to design basic antennas. That should also help.

Please wake me up if anything productive happens.

Thank you jack of all trades,

lyn:

polypropylene or polycarbonate, and/or silicone and hard rubber or thermoplastic polyurethane (TPU)

think plastic Samsung Galaxy S phone-case

inside the box? Surprise, a Samsung Galaxy S

by "all directions" I mean a spherical range of radius 20 ft, or more realistically a rectangular prism array of antennae

ptag = sensitivity

Maximum distance tag can be read = wavelength of signal/(4pi) * sqrt(EIRP/P_tag)

where equivalent isotropic radiated power is EIRP, which = PτG,

where P is the reader output power, τ and G are the impedance matching coefficient and the gain of the reader antenna respectively

Bare in mind that the cell phone 3G, Wi-fi, etc frequencies are an order of magnitude larger and hence the antenna length is much smaller than what you will need.

What are your target receivers anyway? Can you supply more detail on the actual application for us?

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Perhaps a fractal/phased array tuned to that frequency?

Someone wake Lyn up.

Yes I was also thinking of a fractal antenna pattern, specifically a Hilbert Curve due to its simplicity (had to look up its technical name).

Lyn: Wake up.

(That was out of courtesy to Unredundant). XD

Unredundant: That's about where I'm at with my design research (fractal arrays). I'm not that well versed in antenna design (or engineering in general, due mostly to inexperience not lack of study) however.

"Jack of All Trades", "Lyn"and "Unredundant": I realize I'm being a bit vague, but I had to get permission just now to release details of the application:

• The box contains (in addition to an object strangely like a Samsung Galaxy S) a printed circuit that can broadcast the aforementioned MHz frequencies to at least 20 ft.
• The transponder is a passive UHF RFID tag.
• the conditions: the transceiver (the reading circuit on our box) and transponders should be able to respond in any weather condition one might expect from a large city (like say New York).

What I'm concerned with at the moment is antenna design.

Let me know what your other feasibility concerns are for the model.

I realize I'm being a bit vague, but I had to get permission just now to release details of the application

Sooooo your manager knows you are asking an online forum for product development help. That's nice for a change.

Looks like the next step is some more research into fractal arrays to see if you can find a suitable pattern. Hint - this is not new so chances are you can find an existing design in one of the online papers or antenna suppliers without having to design and test something from scratch.

Been gone a little while from this thread.

This is to everyone, but I'm replying to Jackofalltrade's post:

I've run the following calculations in the Connect802 Calculator. Can anyone tell me how reasonable they are for application I described (e.g. do you think the values for antenna gain and length + tx power output are realistic estimates on my part)? Antenna 1 is the interrogator, antenna 2 has the tag data specs.

Initial data for RFID

Also I'm looking for free antenna design software that can help model fractal phased arrays, any recommendations (i.e. Connect802 is a pretty good calculator, saved me the trouble of having to search for a decent one)?

I mentioned phased array as a way to optimise each antenna element involved. The switching frequency would have to be above the point at which the signal would appear as Interrupted from any point.