Omnidirectional gaussian pulse transceiver antenna?

[nabla101]

Hi,

I want to transmit and receive a short (300ps) gaussian pulse for use in a time of flight RF distance measurement scheme (Which has a UWB, bandwidth of 3.3GHz?)

I want a transceiver to be able to transmit the pulse to another transceiver, which can then retransmit the pulse (With a known delay) back to the original transceiver, which calculates the round trip time.

I have seen a system using an omnidirectional broadband planar monopole antenna as the transmitter, and a directional vivaldi antenna array as the receiver (Has to be pointed towards the transmitter), however, it is important in my application to have a single omnidirectional antenna for each transceiver, which can be used as transmitters and receivers, and I so I want to know if this can be acheived with the broadband planar monopole antenna design, or if not, which type of antenna I can use to acheive this.

I have limited expertise in this field so please go easy.

Cheers

 

[ferdows]

its related to your system to how u want to use antennas if u want to change vivaldi to an omni directional antenna i think your system RMS increase so its not useful

 

[nabla101]

its related to your system to how u want to use antennas if u want to change vivaldi to an omni directional antenna i think your system RMS increase so its not useful

Thank you, but I'm not sure I understand what you mean by the system RMS.

I thought that the "reciprocity" of all antennas, means that whatever radiation pattern they have as a radiator when transmitting was identical to the sensitivity pattern, when used as a receiver, and therefore if a planar monopole antenna is an omnidirectional transmitter, then it is also an omnidirectional receiver. I have also read that I can use a radio diplexer to allow me to simultaneously transmit and receive with the same antenna.

For this reason, I'm unsure why they needed a different type of antenna (Vivaldi) for the receiver.

I'm guessing it must be something to do with the bandwidth of the antenna, especially since the system in an ultra-wideband system (UWB), but they don't make this clear in their paper.

I was hoping someone could give me a good technical description of why this is.

Is the bandwidth of a vivaldi antenna better than a planar wideband monopole antenna, at the expense of being more highly directional? Well if so I don't understand how, since antennas are all meant to be reciprocal, and the transmitting planar monopole antenna clearly has the bandwidth to transmit the signal, so why would it not have the bandwidth to receive it?

Thanks

 

[volker_muehlhaus]

Monopole is omnidirectional in one plane, but narrowband.
Vivaldi is wideband, but directional.

If you need an omnidirectional broadband antenna, have a look at this:
https://en.wikipedia.org/wiki/Biconical_antenna

 

[ferdows]

which paper u are talking about ??????
bandwidth of Vivaldi antenna too much than other common antenna and it has some benefit in its phase center and gain and its usually microstrip and so it has easy fabrication but in planar like discone its difference but its related too your and its true antennas are reciprocal and i dont if your system array of this antenna or else?

 

[nabla101]

Monopole is omnidirectional in one plane, but narrowband.
Vivaldi is wideband, but directional.

If you need an omnidirectional broadband antenna, have a look at this:
https://en.wikipedia.org/wiki/Biconical_antenna

Thank you, that explains why they use vivaldi antennas for receiving then, but I don't understand how a UWB system can use a wideband planar monopole antenna as a transmitter, as surely it still needs the same high bandwidth for transmitting sub-nanosecond pulses, as the reciever needs for receiving them.

Also, the design I saw had a planar monopole antenna printed on a circuit board, and I was hoping to use the same compact printed antenna in my design. Are you sure such an antenna cannot be used instead of a directional vivaldi antenna? And if so, then is there an equivalent to the biconical antenna for compact pcb printed ploanar antennas.

I need to be able to tranmit and recieve omnidirectionally in the horizontal plane, with an ultra wide bandwidth capable of transmitting and receiving sub-nanosecond gaussian pulses, and they need to be compact such as a planar, microstrip-fed design, printed on a pcb.

 

[volker_muehlhaus]

I was thinking of the wrong monopole antenna. There are special PCB "monopole" designs for UWB.

**broken link removed**

 

[nabla101]

I was thinking of the wrong monopole antenna. There are special PCB "monopole" designs for UWB.

**broken link removed**

Thanks alot