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Updated README
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bmike2047 committed Sep 5, 2024
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Expand Up @@ -6,53 +6,54 @@ Dipole RF Calculator
<a href="https://github.com/bmike2047/dipole-rf-calculator">https://github.com/bmike2047/dipole-rf-calculator</a>

### Description
Calculates Ez field from a half-wave dipole antenna at distance r<br/>
Calculates VOC (V open circuit) from the incident field Ez on an identical receiving dipole antenna at distance r <br/>
Calculates Pload (power delivered to a perfectly matched load) by the incident field Ez on an identical receiving dipole antenna at distance r <br/>
Calculates Ez field from a half-wave dipole antenna at distance r.<br/>
Calculates VOC (V open circuit) from the incident field Ez on an identical receiving dipole antenna at distance r. <br/>
Calculates Pload (power delivered to a perfectly matched load) by the incident field Ez on an identical receiving dipole antenna at distance r. <br/>
Calculates Prx (power received to a perfectly matched load) via Friis formula.

### Other features
Calculates dipole length from input frequency for a quick antenna design<br/>
Calculates dipole feed current Ia from input power<br/>
Converts both Tx and Rx power to dbm for a quick link budget design<br/>
Calculates dipole length from input frequency for a quick antenna design.<br/>
Calculates dipole feed current Ia from input power.<br/>
Converts both Tx and Rx power to dbm for a quick link budget design.<br/>
Calculates the free space path loss for a quick link budget design. (this includes both Tx and Rx 2.15db gain)<br/>
Computed results are displayed in engineering format<br/>
Computed results are displayed in engineering format.<br/>

### Quick math
First the following assumptions are made:
* dipole antenna has a half-wave length meaning radiation resistance Rrad = 73.08 &#937;
* Ez represents the electric field in Cartesian coordinates and is identical with E&#952; with &#952;=90&#176; in spherical coordinates
* VOC, Pload and Prx are calculated on an identical receiving dipole antenna and polarization at distance r
* both Tx and Rx dipoles have a gain of 2.15db or 1.642
* dipole antenna has a half-wave length meaning radiation resistance Rrad = 73.08 &#937;.
* Ez represents the electric field in Cartesian coordinates and is identical with E&#952; with &#952;=90&#176; in spherical coordinates.
* VOC, Pload and Prx are calculated on an identical receiving dipole antenna and polarization at distance r.
* both Tx and Rx dipoles have a gain of 2.15db or 1.642.

Ez formula below contain the classic Ia current, space impedance and decreasing with distance r<br>
The trigonometric terms are caused by the sinusoidal Ia current distribution on the antenna (doughnut shape)<br>
Ez formula below contain the classic Ia current, space impedance and decreasing with distance r.<br>
The trigonometric terms are caused by the sinusoidal Ia current distribution on the antenna (doughnut shape).<br>
<img src="assets/images/half-dipole2.gif" width="370px">
<br/>

VOC formula below is the Ez*l but because the receiving antenna also has a sinusoidal current distribution it gets multiplied again by the trigonometric terms above<br/>
This leads to the tan function squared because of the 2 identical dipoles<br/>
VOC formula below is the Ez*l but because the receiving antenna also has a sinusoidal current distribution it gets multiplied again by the trigonometric terms above.<br/>
This leads to the tan function squared because of the 2 identical dipoles.<br/>
<img src="assets/images/half-dipole3.gif" width="320px">
<br/>

Pload formula below is constructed from converting to rms and perfectly matching the load to the antenna<br/>
Pload formula below is constructed from converting to rms and perfectly matching the load to the antenna.<br/>
<img src="assets/images/half-dipole4.gif" width="150px">
<br/>

**Verification 1**<br/>
Friis formula below is use to verify all calculations above<br/>
It takes into consideration both dipole's effective aperture area<br/>
Friis formula below is use to verify all calculations above.<br/>
It takes into consideration both dipole's effective aperture area.<br/>
Given freq=2.4GHz, Ptx=36.54W, r=200m our calculator gives Pload=243nW. Using the Friis formula below we also get Prx=243nW.<br>
<img src="assets/images/half-dipole5.gif" width="210px">
<br/>

**Verification 2**<br/>
CST studio was used to calculate the electric field for freq=2.4GHz, Ptx=36.54W, r=200m<br/>
This resulted in 0.2989V/m (screenshot below) while our application returned 0.3V/m (see screenshot at the end of this file) which is pretty good for our sinusoidal current distribution approximation<br/>
CST studio was used to calculate the electric field for freq=2.4GHz, Ptx=36.54W, r=200m.<br/>
This resulted in 0.2989V/m (screenshot below) while our application returned 0.3V/m (see screenshot at the end of this file) which is pretty good for our sinusoidal current distribution approximation.<br/>
![](assets/images/cst.png)
<br/>

### Usage
Requires JDK 17<br/>
Requires JDK 17.<br/>
To run the project use the following command:<br/>
```
./gradlew clean run
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