Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

What ANTENNA do you recommend???

Status
Not open for further replies.

kevinj

Advanced Member level 4
Joined
Jan 19, 2006
Messages
118
Helped
8
Reputation
16
Reaction score
4
Trophy points
1,298
Activity points
2,233
I want to design an antenna at 915MHz on PCB (x-y plane). I want it to be omni-directional in the x-y plane.
 

savedadogs

Full Member level 1
Joined
Dec 11, 2003
Messages
95
Helped
18
Reputation
36
Reaction score
7
Trophy points
1,288
Location
California
Activity points
762
I suggest using a circular patch antenna shorted in the center to make the TM_010 mode dominant for the coverage you require. This is a simple and planar antenna.
 

kevinj

Advanced Member level 4
Joined
Jan 19, 2006
Messages
118
Helped
8
Reputation
16
Reaction score
4
Trophy points
1,298
Activity points
2,233
Savedadogs,

How do you feed it? With a microstrip?

Do you have a simple drawing?
 

savedadogs

Full Member level 1
Joined
Dec 11, 2003
Messages
95
Helped
18
Reputation
36
Reaction score
7
Trophy points
1,288
Location
California
Activity points
762
Yes you can simply feed it with a microstrip feed. You may need to use capacitive coupling to match to the impedance. I dont have a drawing but it is a very simple structure...just a circular patch shorted in the center. You can also just use a regular square patch antenna shorted in the center to create the same pattern. By shorting the center of the rectangular or circular patch antenna you are forcing the field to be zero in the center and max at the edges, thus providing you with the pattern you want. You can also look at a paper by Lai, Leong, and Itoh on a dual-mode antenna which was presented at last years asia pacfic conference...it had the pattern you are looking for.
 

savedadogs

Full Member level 1
Joined
Dec 11, 2003
Messages
95
Helped
18
Reputation
36
Reaction score
7
Trophy points
1,288
Location
California
Activity points
762
Isn't a Yagi very directive...it seems like he/she wants a omni-directional antenna.
 

plasma

Advanced Member level 2
Joined
Dec 20, 2001
Messages
536
Helped
79
Reputation
158
Reaction score
41
Trophy points
1,308
Activity points
3,854
I have example for you

PL
 

kevinj

Advanced Member level 4
Joined
Jan 19, 2006
Messages
118
Helped
8
Reputation
16
Reaction score
4
Trophy points
1,298
Activity points
2,233
Plasma, your antenna is printed in the x-z plane and has omni directional in the x-y plane.

Savedadogs, thanks for referring me to a paper. I'm working on getting it, though it's difficult because it was presented at a conference in China, just like you said.

A. Lai, KMKH Leong, and T. Itoh
Dual-mode compact microstrip antenna based on fundamental backward wave
Asia Pacific Microwave Conference

You are also correct in that I'm looking for an omni-directional antenna.

I'm going to simulate an antenna based in the circular structure you described previously.

The results are below. The first plot is an x-y slice at theta = 90 degrees (E phi plane). I used a pcb thickness of 1.6mm. The radiation pattern isn't really what I'm looking for. Maybe I don't understand your description of the fixed antenna. I know that if you use an antenna that is fixed off the pcb by 7 to 10 mm then you can get an omni directional pattern, but that isn't a simple pcb printed antenna. Is that what you are talking about?
 

kevinj

Advanced Member level 4
Joined
Jan 19, 2006
Messages
118
Helped
8
Reputation
16
Reaction score
4
Trophy points
1,298
Activity points
2,233
I got the paper. Hopefully the author doesn't mind.
 

Element7k

Advanced Member level 1
Joined
May 7, 2003
Messages
434
Helped
26
Reputation
52
Reaction score
19
Trophy points
1,298
Location
TherealLapland
Activity points
4,278
Hi,

try changing the scale of your graph to log and also change the range to maybe 40dB.

Element7k
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top