Anyone Help me to design Low frequency UWB antenna

[kyawsoelwin]

Dear All,

I tried to design patch antenna or sprial patch antenna . I wanna to get 40MHz range. thanks for ur all advances.

regards,
kslwin

 

[vfone]

Question: what means “40 MHz range” for an antenna?

 

[kyawsoelwin]

Dear Vfone,

thansk for ur reply.

sorry! for my wrong usage. I mean 40MHz resonant freq and 10dB bandwidth of around 40MHz. that's my interesting freq range. I tried to simulate C-patch sprial antenna with CST mircrowave studio. I cann't get satisfy results.

I don't need good radiation. just for near field usage like RFID.

I wanna to know,

1) It's possible
2) If possible, kindly help me which art of patch or antenna design.

Regards,
kslwin.

 

[Azulykit]

A resonant patch at this frequency would be several meters on each side and I suspect that is too big.

You probably should look into "electrically small" antennas and I suspect that you will see gains on the order of -5 to -10 dBi at best.

How far does the link need to operate? How big an antenna can you tolerate? Is high power involved? The 40 MHz bandwidth centered at 40 MHz might also be a challenge. Waht is the application like? Defining that may help your search for an appropriate antenna.

 

[kyawsoelwin]

Thanks for ur reply Azulykit,

you are right! it will be several meter patach to get that resonant frequency. but , I wanna to reduce size to a few centimeters size, tiny fraction of λ .

It will be applied to detecting radio-interfence from High Voltage Equipments. so it's just for recieving(detecting) within 1 or 2m range. It doesn't need for radiation.

I think gain of -5 to -10dbi is enough for that application.

Dear All,
any comments you have about specail art of patch, or any idea
Help, I am now still trying by using CST .

Thanks again to all.

 

[vfone]

The gain of this “tiny” fraction of λ patch antenna would be less than you expect.
Try a spiral or a multi-turn loop antenna that will work acceptable for your application.

 

[Azulykit]

Just for another reference, The gain of an open coaxial connector is about -20 dBi. You may want to see if that is enough for your particular application.

 

[kyawsoelwin]

Dear All,

Thanks for all of ur advises.

...... Dear Azulykit,

The gain of an open coaxial connector is about -20 dBi.

Sorry! I don't understand how connector can be used to obtain such gain of -20dBi.

I understand It's just attenuation of -20dB block of connector loss.

Pls kindly explain me what you mean, if u have a time,

Thanks for ur time.

regards,
kslwin.

 

[Azulykit]

I was curious about the leakage from an open connector and decided to make a measurement to see where it might lead.

I disconnected the test antenna on a far field range (4 GHz) and took a radiation pattern and it turned out that I was seeing an "antenna" with -20 dBi and a roughly omni-azimuthal radiation pattern.

Think of this as an antenna with about 1 percent of the efficiency of a dipole. Actually I was somewhat surprised to see radiation at this level. I would anticipate similar performance by an electrically small antenna.

You might also want to look into the ambient man made noise at HF frequencies. It is considerably higher than that encountered at microwave frequencies. That may factor into your design as well.