RomanD2
Electrical
- Jan 27, 2004
- 4
Can anybody help me?
I found a mathematical method to inrease the range of radio tracking transmitters. I achieved about 50 miles with a 14 mm loop Antenna and a PLL - IC. Now I want to make some of those transmitters and sell them.
The problem is - I have very less experience in RF!!!
I understand how a tank circuit works and what a matching circuit is for. But I can not calculate the values of the coil and capacitors. I saw many design notes to match RF IC´s with class c amplifier to 50 Ohms - but just one for a loop antenna - and that had poor range.
My IC has an 2,7V / 10 dBm class C - amplifier
I have a coil (about 22...100 nH) to feed the amplifier
and a capacitor (1,8....8 pF) for oszillation at 433 Mhz.
The loop antenna has 14 mm Diameter and 1mm thick copper wire. The antenna has an capacitor with 4,2 pF / ESR= 30 mOhm for oszillation at 433 Mhz. It should have an total ESR of 0,25 Ohm.
I use an capacitor about 0,7 pF to connect antenna and IC/tank circuit.
The circuit is SMD 0402, has short wires <4mm, and a power plane under 0,5 mm thin BCB.
Can anybody give me some help? If anybody want to calculate it for me I would be very happy - but just the formulars, a book or a link would help too.
I found a mathematical method to inrease the range of radio tracking transmitters. I achieved about 50 miles with a 14 mm loop Antenna and a PLL - IC. Now I want to make some of those transmitters and sell them.
The problem is - I have very less experience in RF!!!
I understand how a tank circuit works and what a matching circuit is for. But I can not calculate the values of the coil and capacitors. I saw many design notes to match RF IC´s with class c amplifier to 50 Ohms - but just one for a loop antenna - and that had poor range.
My IC has an 2,7V / 10 dBm class C - amplifier
I have a coil (about 22...100 nH) to feed the amplifier
and a capacitor (1,8....8 pF) for oszillation at 433 Mhz.
The loop antenna has 14 mm Diameter and 1mm thick copper wire. The antenna has an capacitor with 4,2 pF / ESR= 30 mOhm for oszillation at 433 Mhz. It should have an total ESR of 0,25 Ohm.
I use an capacitor about 0,7 pF to connect antenna and IC/tank circuit.
The circuit is SMD 0402, has short wires <4mm, and a power plane under 0,5 mm thin BCB.
Can anybody give me some help? If anybody want to calculate it for me I would be very happy - but just the formulars, a book or a link would help too.