Problem about loop and bended monopole antenna

[Mac7978]

monopole bended

Hi all,

As i am not at english, i hope u all can understand what i mean @_@...

Receently, i had design a frame antenna which is bended like a rectangular loop and the total length is λ/4. This antenna has two ends, one is connected to the input of an receiver. For the other end, if it is connected to the ground, the antenna is a loop antenna, and if it is keep open, then the antenna is a bended monopole. At last, this antenna is put over the receiver's circuitry.

My problem is that if omni-directional antenna is required, should i connect one end of the antenna to ground or not?

After do the measurement, i am confuse as the performance of a loop and bened monopole antenna seem the same.

Please give me some advices, thank a lot.

Best rgd.

 

[flatulent]

a bended monopole

This antenna is of the family type called "folded dipole" and the two parallel wire portion performs an impedance transforming function. If the wires are of equal diameter the transforming ratio is 4 times which makes the feed impedance 300 ohms. For the monopole over a ground plane the impedance is 150 ohms. To keep the unwanted loop antenna effect down the parallel wires should be cloese together.

 

[bsiswoyo]

what is monopole loop antenna

Please explain the frequency that you used. (fc, bandwidth)