Building 433.92 MHz antenna on PCBs

[nikhilele]

i have 433.92Mhz modules I want to make a antenna of about 2-6cm on the pcb for short range communication. so what thickness i have to keep
i am using glass epoxy grade 4, with thickness 1.6mm.

I will glad to know from the exprience of the pcb designers who had deisigned the antennas on simple pcb's.

 

[jallem]

pcb antenna 433mhz

for 433.92 MHz any pice of wire will do.
It is not the best antenna but it will work.
Do not put any reflecting surface close to it.

 

[nikhilele]

433.92mhz helical antenne

if i made a track on pcb then it will work as antenna
I donot have much space on pcb it 6 to 9 cm only.

what width i should keep to have good radiation,

 

[brendan99]

trace as antenna

make the track 1.5mm wide and 173mm long. Place it at the edge of the PCB and go around the corner if you need to. Keep other stuff 15mm away if possible. This should give you a return loss of about -8dB. Wont be a great antenna but will work fine at short range. I'd guess 40Meters indoor with a TX power of +10dBm indoors.

 

[nikhilele]

433.92 pcb antenna tx

i donot have 17cms space on my board.
I know 17cms is antenna lenght for 433Mhz.
shorter lenght will give shorter range.

can we increase range by resonating the track.
I want to say that track has its own inductance and if we connect the capacitor then we can resonant it at 433mhz so how is my idea.

so we can discuss on this too.

 

[brendan99]

pcb helix antenna

see page 2 here
**broken link removed**

Brendan.

 

[nikhilele]

long trace antenna in pcb

1>
The dimension and the value of the commponents given there may be specific to their module. As these things highly depends on the ouput impedance of the transmitter.

I have extracted important portion from the file

see page 2 here
h**p://www.rfsolutions.co.uk/acatalog/DS012_1.pdf

which i am posting here.


2>
(a)
why it is written it is not approved for quarter wave or helical antenna
(b)
and if the area exceeds 700mm² then the antenna lenght will be greater then quarter wave length then what side effect we will see. i.e how the radiation will decrease

sorry for bombing questions

 

[brendan99]

pcb trace 433mhz antenna

I expect antennas shown are for connecting to a 50Ohm soyrce. Are u using a module or a chip? What is part number?

The type approved thing just means they have not tested for ISM band requirements.

If your source is 50Ohm, you want your antenna Zo 50Ohm. If you shorten antenna, current and voltage are not at correct phase angle. The antenna is not 50Ohm but a complex impedance e.g. 35-j120. you can then add a reactance to the antenna circuit to offset this.

Less radiation is because of increased parasitic losses in reactive tuning elements. Effectively antenna Q is lower.

 

[nikhilele]

trace antenna pcb

Are u using a module or a chip? What is part number?

i am using a module similar to TWS434

I am attaching the datasheet of most common and widely used module
and same I am using.

SM TX – 4 is similar to TWS434
I am attaching data sheet of both