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Need advise on designing microstrip antenna 315MHz

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zeese

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tx/rx antenna 315 mhz

Hi...
I need advices from everybody on how to design a microstrip antenna (on pcb)
for 315mhz. For Tx, it's a loop antenna, and rx, it's a monopople PCB trace antenna.
Also, one more thing, I just need to do transmission for a short distance
only about 3 or 4 meters. Once, I just bluntly design the antenna as has suggested
by the datasheet of the tx/rx IC but it only works for not even 1 meter.

Also, is the antenna dimensions important? Isn't it the longer the antenna, the better it
is.. so, why do I need to calculate dimensions?

The pcb has limited space for antenna, i need to increase the range without increasing
the space that antenna used.

This is my new assignment in my workplace, even though I really have no idea, no
experience in this thing. Never taken antenna design course. So, I need quidance
and maybe some reference on me to do research and study.

You help is appreciated.
 

Element_115

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315mhz pcb antenna

Well 315MHz is a very long wave length (for a PCB).
WavLen=C/F
C=speed of light
F=Frequency

--> WavLen~0.95Meters ~ 2.8 ft
anntenas are usually (1/4) WavLen --->8.5 inches long
in a dipole configuration you'll need 17inches + sum buffer room

|
| 8.5inches (+)
|
[ TX ]========
|
| 8.5inches (-)
|

Plus you need to calulate Zo, is it 50ohm's or 75ohm's
I think "HP APLAC" dose this, or search for other free microstrip tools.
They will explain some of the other parameters to consider.

Hope this helps
Cheers
 
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DanTheMan

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315 mhz patch antenna

Usually at this frequency there's no patch antenna. Now designing something for the 12 GHz band...different matter 8O
 

Element_115

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loop antenne 315mhz

Hey, Look for "APCAD" not APLAC sorry about that
APLAC is Nokia's Desing simulator.
 

dsp2x

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315mhz antenna design

h**p://www.kilomega.com/software/awas.zip

Hope a little help
 

pkg

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Re: tx/rx antenna 315 mhz

Hi...
I need advices from everybody on how to design a microstrip antenna (on pcb)
for 315mhz. For Tx, it's a loop antenna, and rx, it's a monopople PCB trace antenna.
Also, one more thing, I just need to do transmission for a short distance
only about 3 or 4 meters. Once, I just bluntly design the antenna as has suggested
by the datasheet of the tx/rx IC but it only works for not even 1 meter.

Also, is the antenna dimensions important? Isn't it the longer the antenna, the better it
is.. so, why do I need to calculate dimensions?

The pcb has limited space for antenna, i need to increase the range without increasing
the space that antenna used.

This is my new assignment in my workplace, even though I really have no idea, no
experience in this thing. Never taken antenna design course. So, I need quidance
and maybe some reference on me to do research and study.

You help is appreciated.
can u explain me about how to design that patch antenna.
thank you.
 

biff44

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there are plenty of applications that print 315 MHz antennas on a small PCB. A handheld keyfob is a typical example.

The loop length of the antenna is much shorter than the length required for resonance. One way to overcome that is to add a series reactance in the loop to "tune it" to 315 MHz.

Also, since he loop is too small physically, it will not radiate energy into free space with great efficiency.
 

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