Antennas for RADAR at 2.5 GHz

Hi I want to buy 2.4 GHz directional antennas for Doppler RADAR I have designed. Kindly note that I am not good in antenna theory. I tested dipole antennas I somehow got but problem is Signal directly received by receiver antennas from transmitter is too high to get the reflected signal back. Is there any place I can get suitable antennas(COTS) may be horn with at least 12 dbi gain
thanks



Also note that I am using SMA connector for transmitter and receiver so Horn with waveguide input wont work
thanks in advance

I reposted this one as earlier I incorrectly mentioned frequency as 2.5 GHz
Hi I want to buy 2.4 GHz directional antennas for Doppler RADAR I have designed. Kindly note that I am not good in antenna theory. I tested dipole antennas I somehow got but problem is Signal directly received by receiver antennas from transmitter is too high to get the reflected signal back. Is there any place I can get suitable antennas(COTS) may be horn with at least 12 dbi gain

Also note that I am using SMA connector for transmitter and receiver so Horn with waveguide input wont work
thanks in advance

I do not know details of your Doppler radar. A typical DR consists of a transmitter, a receive mixer, a circulator and a RF coupler. Such design allows to use one antenna to transmit and receive. The type of antenna is selected for a desired range and directional pattern.

Even simpler designs a say 2.4 GHz use an oscillator and coupled detector as a mixer, both connected to one antenna. (e.g. ramseykits.com). The TX leakage to receiving mixer in not a problem as the beat frequency results from mixing the TX and RX signals.

Using two antennas obviously not needed. If an antenna is waveguide type, you can use a transition to coaxial or stripline port.

"Standard gain" horns fall in the range you cite. A search will turn up numerous options. I would expect a horn and transition would go for a few SK.

Azulykit

I'm not sure if a dipole antenna is appropriate for a radar. Since it is not an directional antenna you are always scanning in nearly all directions and you don't know from witch direction the response is coming.

the dipole would generally be placed in front of the reflector

Dave

Best if you offer details of your radar so we can see what is needed

hey thanks for reply
Yes i think horn would work fine. Dipole as usual is not transmitting in one direction rather in many. I am not sure how much horn would typically cost?
few 1000 S you said?
that is too much
thanks

Pity you gave no technical details of your system so we can offer qualified advice.
You can buy a horn for S500 or S3k but you can make one for almost no cost.
But I do not know what specifications you need.
Check LCOM.com for commercial antennas.

Hey sorry was in a bit of hurry.
In my radar I am using a trasmitter to transmitt 2.4 GHz sine wave. I have a separate reciver board which has a mixer IC and low noise amplifier. A part of signal transmitted from trasmitter using antenna(which earlier i was using dipole but now i am switching to horn). other part of the same signal is given to receiver using 3 db splitter as LO input to reciver. Receiver has one separate antennas which receives signal reflected from moving target Mixer mixes reflected signal and LO signal to get frequency shift which is measured using NI DAQ. That is why I need two antennas. Problem with dipole is signal which is directly received is too strong so reflected signal is extremely weak and comes in noise floor. Let me know if you need further detail.
Thanks

http://www.pasternack.com/standard-g...64sf-20-p.aspx

http://www.ebay.com/itm/Antenna-Pane...item540270403c

http://www.ebay.com/itm/New-2-4GHz-1...item27d59a1575

I miss technical specifications, e.g. what antenna gain you need, or TX power and required radar range. Designing an antenna requires to know just that.

I am transmitting 5dBm but after 3 dB splitter power going into antennas is 2 dBm. 2.4 GHz is freq I am transmitting as already mentioned and also gain of antenna I am looking for atleast 15dbi now

For >15 dB gain you can use a horn (commercial models start from S400 for a 23 dB horn), a Yagi (check "L-Com.com") or a dish (L-Com).
For low-cost make a horn of thick paper, plywood or glass laminate and glue aluminum foil on its active surface to make it conducting. You can paint it and make it look professional after testing your radar.

hey jiripolovka thanks that helped a lot
Is there any quick tutorial or something of that sort to get me in a direction so that i can get started. I am not that good with antenna

I know old good textbooks on antennas, by J.D.Kraus, by Harvey, Microwave Engineering, and more. Horns are possibly the easiest to design.