Best Antenna and Rectifier Diode

Click For Summary

Discussion Overview

The discussion revolves around maximizing voltage received from an RF antenna and selecting an appropriate rectifier diode. Participants explore various aspects of antenna design, impedance, and diode characteristics, with a focus on practical applications and considerations for building a rectenna.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • Some participants suggest that a high impedance antenna, such as a tuned loop or rhombic array, may maximize voltage output.
  • Others recommend using low loss 50 ohm coax cable and minimizing connectors to reduce signal loss.
  • There are mentions of different types of rectifier diodes, with germanium diodes noted for low voltage drop, while synchronous detectors made from MOSFETs are also proposed as alternatives.
  • One participant emphasizes the importance of knowing the operating frequency to select or design an appropriate antenna.
  • Concerns are raised about regulatory issues related to frequency use and potential legal implications of energy harvesting from local transmitters.
  • Some participants inquire about the specific application and frequency to provide more tailored advice.
  • There are suggestions to procure antennas from various sources, including commercial vendors and surplus stores.
  • Participants express the need for more details about the user's goals to provide useful guidance.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best approach or specific recommendations, as multiple competing views and uncertainties about the user's application and frequency persist throughout the discussion.

Contextual Notes

Participants highlight the dependency of antenna impedance on operating frequency, the importance of understanding local regulations, and the need for clarity on the user's specific goals and requirements.

Who May Find This Useful

This discussion may be useful for individuals interested in RF antenna design, rectenna construction, and those seeking advice on diode selection for energy harvesting applications.

  • #31
To extract significant power you must tune your antenna and the coupling to the rectifier. The tuning will be frequency dependent so all your frequencies will need to be within about one percent of each other.

There is also the problem of direction. To capture significant energy you need to aim your antenna, or it's reflector. Unfortunately, multiple transmit sites will probably not be in a line and in the same frequency band.
 
Engineering news on Phys.org
  • #32
Thank you all for your help. This discussion can be closed.
 
  • #33
45tt, designing an antenna is not something that everyone can do. There are so many applications, types and considerations of antenna design that only professionals can design an antenna that can actually transmit some power. There are so many different types of antenna for so many different types of frequency with so many different power output specifications. For anyone to answer this question, it is important that you mention how much gain is required as well.
 

Similar threads

Replies
7
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 10 ·
Replies
10
Views
4K
  • · Replies 14 ·
Replies
14
Views
2K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 37 ·
2
Replies
37
Views
4K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 28 ·
Replies
28
Views
7K