Printed dipole mounted on reflector ground plan ： XFDTD 7.0

Hi there,

I am working on printed dipole antenna array.
I an new for XFDTD design, and I really need help.

For making understanding, I started to design Microstrip ; one end I put feed component 50 ohms
and put passive load 50 ohms on the other end. The result was as I expected.

After that, I designed a patch antenna at 2.4 GHz and it provided a good agreement compared to the measurement.

But the problem occurred when I was design a printed dipole that mounted on the reflector ground plan.
S11 is almost zero throughout possible frequencies. I would like it to match at 1.9 GHz.

I don't know what's wrong with my design. Anyone can help me I am very appreciate.

You're sure the ground plane is λ/4 away from the dipole?

There's a great tutorial in Balanis on dipole arrays and impedance matching.

Yes, I am sure because I have designed it on WIPL-D before.
Then I brought the same dimension to design on XFDTD, and I don't know what's wrong.

Well, sorry, but that's outside my scope of knowledge then :/

Good Luck!

Thank you for your concern PlanarMetamaterials, I will find it out soon.
However if anyone has an experience about XFDTD please help me. I am in a rush hour!

Anyone could direct or guide me, please?
Trying to simulate, but never get close to the result as I expected.

can you post your design? I can try to run it in another software and see what is exactly going on.

Attachment 82602

Here is the antenna I want to simulate.
I will design it on FR-4 with the thickness of 1.6 mm, and dielectric constant is 4.4.
The dimensions are shown below.

Wd = 15 mm
Ws = 1 mm
Wg = 30 mm
Wm = 17 mm
wm = 3 mm
Hm = 15 mm
Lm =16 mm

and the reflector ground plane is 160*200

- - - Updated - - -

Printed Dipole Structure.bmp

Here is the antenna I want to simulate.
I will design it on FR-4 with the thickness of 1.6 mm, and dielectric constant is 4.4.
The dimensions are shown below.

Wd = 15 mm
Ws = 1 mm
Wg = 30 mm
Wm = 17 mm
wm = 3 mm
Hm = 15 mm
Lm =16 mm

and the reflector ground plane is 160*200

Looking at your picture, you marked a "Shorted Stub" pointing in the middle gap between the two microstrips. Where is this shorted stub connected to? Typically, you connected the two dipole patch together and then connect them to ground. I am curious on how you connect the two dipole patch into the same ground in XFDTD. you extrude them until they both touch a PEC boundary?

Well, normally this type of antenna is like you described, that is two dipole patches interconnected before then they connected to the ground.
But this antenna, he achieve matching by adjusting the bulun, and the slot line acts like short stub. If you cannot imagine I can send you a paper, and maybe you will get a full understand how it work.

For my design in XFDTD, it still have a problem about the reflector ground plane. I really have no idea how to deal with it.
As I've been designing, I tried to avoid defining PEC boundary, that I designed a sheet body to be a reflector ground plane.

Please leave you e-mail address, I will send you the paper.
Thank you so much.