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stripline for 13.56 MHz
Hello to everybody,
first of all I say sorry for my bad English and for my really bad knowledge. I'm projecting an antenna for RFID (13.56 MHz) and I don't know if is possible to use a strip line with this frequency. I've seen that in some books there are some theory equations regarding GHz, but nothing about Mhz. Is the wavelenght too long compare to the dimension of a stripline? Thank you, Massimo |
A half wavelength at that frequency is about 10 meters. Hard to fold that
up in a small tag. Figure all dimensions are 1000X when translating from microwaves to HF. -- Crazy George Remove N O and S P A M imbedded in return address "Massi" wrote in message ... Hello to everybody, first of all I say sorry for my bad English and for my really bad knowledge. I'm projecting an antenna for RFID (13.56 MHz) and I don't know if is possible to use a strip line with this frequency. I've seen that in some books there are some theory equations regarding GHz, but nothing about Mhz. Is the wavelenght too long compare to the dimension of a stripline? Thank you, Massimo |
On Tue, 27 Jan 2004 10:15:57 +0100, "Massi"
wrote: Hello to everybody, first of all I say sorry for my bad English and for my really bad knowledge. I'm projecting an antenna for RFID (13.56 MHz) and I don't know if is possible to use a strip line with this frequency. I've seen that in some books there are some theory equations regarding GHz, but nothing about Mhz. Is the wavelenght too long compare to the dimension of a stripline? Thank you, no strip lines necessary, this 13,56 MHz frequency is "DC radio" , a rather low frequency application. Look there for a detailed description: http://www.ti.com/tiris/docs/manuals...esignNotes.pdf w. |
"Massi" wrote in message ... Hello to everybody, [...] I'm projecting an antenna for RFID (13.56 MHz) and I don't know if is possible to use a strip line with this frequency. I've seen that in some books there are some theory equations regarding GHz, but nothing about Mhz. Is the wavelenght too long compare to the dimension of a stripline? Yes. Just use a resonant circuit "open to the air". -- Steve N, K,9;d, c. i My email has no u's. |
Stripline will work fine at 13MHz. I'd expect it to have a
characteristic impedance that's practically identical to what it has at microwave frequencies, for any practical size line. If it's a short run connecting to a load that's the same impedance as the line, that's probably all you need to know, but if you're using it for a matching stub or series matching section, you'll need to worry about loss and propagation velocity and things like that...and in general, at 13MHz you'll find it more efficient in both volume and power loss to use a lumped matching network. Tell us more specifically what you are trying to do, and we may be able to give more help. Cheers, Tom "Massi" wrote in message ... Hello to everybody, first of all I say sorry for my bad English and for my really bad knowledge. I'm projecting an antenna for RFID (13.56 MHz) and I don't know if is possible to use a strip line with this frequency. I've seen that in some books there are some theory equations regarding GHz, but nothing about Mhz. Is the wavelenght too long compare to the dimension of a stripline? Thank you, Massimo |
From reading between the lines (RFID) I got the impression the OP was after
an antenna not a transmission line. Steve N. "Tom Bruhns" wrote in message m... Stripline will work fine at 13MHz. I'd expect it to have a characteristic impedance that's practically identical to what it has at microwave frequencies, for any practical size line. If it's a short run connecting to a load that's the same impedance as the line, that's probably all you need to know, but if you're using it for a matching stub or series matching section, you'll need to worry about loss and propagation velocity and things like that...and in general, at 13MHz you'll find it more efficient in both volume and power loss to use a lumped matching network. Tell us more specifically what you are trying to do, and we may be able to give more help. Cheers, Tom "Massi" wrote in message ... Hello to everybody, first of all I say sorry for my bad English and for my really bad knowledge. I'm projecting an antenna for RFID (13.56 MHz) and I don't know if is possible to use a strip line with this frequency. I've seen that in some books there are some theory equations regarding GHz, but nothing about Mhz. Is the wavelenght too long compare to the dimension of a stripline? Thank you, Massimo |
On Tue, 27 Jan 2004 10:15:57 +0100, "Massi"
wrote: Hello to everybody, first of all I say sorry for my bad English and for my really bad knowledge. I'm projecting an antenna for RFID (13.56 MHz) and I don't know if is possible to use a strip line with this frequency. I've seen that in some books there are some theory equations regarding GHz, but nothing about Mhz. Is the wavelenght too long compare to the dimension of a stripline? Thank you, Massimo Most people just use a resonant loop and work with the (relatively) low radiation efficiency. Most RFID applications are close range, so the antenna's radiation pattern is of little concern. Many application notes on the web describe calculating the inductance of the loop and the tuning procedures necessary to achieve resonance at the desired Q (which affects bandwidth). Mark |
Thanks a lot for all the answers,
I'm doing some tests in laboratory with a network analyzer and will let you know asap what I will find. Massimo |
"Massi" ha scritto nel messaggio
... Thanks a lot for all the answers, I'm doing some tests in laboratory with a network analyzer and will let you know asap what I will find. Massimo I have done some tests with trasmission line builded in FR4 (30cm long, 2cm wide), according to them I have the following notes: VSWR MICROSTRIP 50 OHM 13.56 MHz = 1.0129 1 GHz = 1.0457 3 GHz = 1.0994 VSWR COPLANAR WAVEGUIDE 50 OHM 13.56 MHz = 1.0250 1 GHz = 1.1698 3 GHz = 1.3500 VSWR STRIPLINE 50 OHM 13.56 MHz = 1.0315 1 GHz = 1.0269 3 GHz = 1.2665 LOSS MICROSTRIP 50 OHM 13.56 MHz = - 0.03360 dB 1 GHz = - 0.83380 dB 3 GHz = - 2.40590 dB LOSS COPLANAR WAVEGUIDE 50 OHM 13.56 MHz = - 0.04660 dB 1 GHz = - 0.84300 dB 3 GHz = - 2.12640 dB LOSS STRIPLINE 50 OHM 13.56 MHz = - 0.06340 dB 1 GHz = - 1.00830 dB 3 GHz = - 3.05160 dB bye, Massimo |
"Massi" wrote in message . .. "Massi" ha scritto nel messaggio ... Thanks a lot for all the answers, I'm doing some tests in laboratory with a network analyzer and will let you know asap what I will find. Massimo I have done some tests with trasmission line builded in FR4 (30cm long, 2cm wide), according to them I have the following notes: VSWR MICROSTRIP 50 OHM 13.56 MHz = 1.0129 1 GHz = 1.0457 3 GHz = 1.0994 VSWR COPLANAR WAVEGUIDE 50 OHM 13.56 MHz = 1.0250 1 GHz = 1.1698 3 GHz = 1.3500 VSWR STRIPLINE 50 OHM 13.56 MHz = 1.0315 1 GHz = 1.0269 3 GHz = 1.2665 LOSS MICROSTRIP 50 OHM 13.56 MHz = - 0.03360 dB 1 GHz = - 0.83380 dB 3 GHz = - 2.40590 dB LOSS COPLANAR WAVEGUIDE 50 OHM 13.56 MHz = - 0.04660 dB 1 GHz = - 0.84300 dB 3 GHz = - 2.12640 dB LOSS STRIPLINE 50 OHM 13.56 MHz = - 0.06340 dB 1 GHz = - 1.00830 dB 3 GHz = - 3.05160 dB bye, Massimo Isn't waveguide kind of big at 13.56 MHz? John |
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