Just finished designing a PCB 915Mhz dipole antenna with impedance matching circuit.
i’ve ordered some for testing and tuning.
What does everyone think of the design?
I would love feedback from anyone who has done antenna tuning with impedance matching.
Are you sure you need impedance matching? A dipole cut to the right length should have reasonable matching. I think you should get about 1.5:1 vswr with no extra components.
Looks good though, I’ve been thinking about trying a dipole myself.
I’m just getting into the community but antenna design is my passion.
Which program did you model it in and have you allowed room in the input circuit for a current choke 1:1?
If you its to be enclosed and the pc board does not have through hole via to reverse side mwtching elements it will not be exactly on frequency. Im old school in wanting my final antennas to be tuned by resonance in design before losing efficiency in matching circuits. If its fabricated at length or slightly longer its possible to change the resonance by cutting the trace to shorten it. And as
Im sure you know anything in the nearfield affects the signal but that to can have allowances in design and by your wisely including switching or tuning a variable capacitance or slug tuned inductor. Very nice product and it goes without saying how effective and simple a good dipole is, Craig KD9UQE
Hi Craig, I used EasyEDA to design the PCB. But I came up with the antenna design from researching coplanar microstrip transmission lines, and simple matching networks and an example PCB dipole design I’ve seen online.
I will design a simple plastic case and will take this into account when I’m tuning it. Will most likely be 3D printed.
I would love do collaborate on the design further. The marching circuit has grounded vias both sides of the board in order for the transmission line to be as close to 50 ohms as possible and then the active element can be tuned to length by either cutting it shorter or by soldering the little jumper to connect the end mounting hole. Then tuning it from there. I’ve also made it so that if I ever get into Ham radio I can solder the two end jumpers and then connect two ring terminals with long wire and I will have the base for any size dipole antenna.
To answer your question regarding the balun 1:1 choke . I may be wrong, but I assumed that the input would be fairly well matched at 50 ohms and would not need much work. But if need be I can use an inline choke. But I hadn’t thought of it, to be honest.
My intention is to solder a 0 ohm resistor to the inductor location and then tune the length as perfectly as I can. Then put it onto a VNA and then see if it needs any inductance matching and then design the set of values that will give me as close to 50 ohms as possible.
Initial testing… It works at least. I need to order a VNA to do full testing and get a number for SWR and populate the matching circuit if required.
Cool project - looking forward to updates
Hey, I know it’s been a little while since there was a post. How did you make out? Does it work?
Have you seen these?
