Saturday, July 12, 2014

BiQuad Antenna Calculator

Introduction

The BiQuad antenna is fairly easy to build and provides reliable gain and it has very forgiving design. You can make quite a big margin of error in the construction and still get 10-11dBi gain. Hence here is the Double BiQuad Antenna and BiQuad Antenna calculators for handmade antenna based on average data.
However I highly recommend to follow my instructions, which are based on computer antenna simulation software 4nec2, to maximize performance. Here is listed currently available instructions, simulated with computer software, for handmade 13-14dBi Double BiQuad external antenna.

Note: The dBi scale is logarithmic in base 10, where +3 dBi is a doubling in gain! An increase in gain of +1 dBi is equivalent to an increase of 26% and +2 dBi is equivalent to an increase of 60%. This means that the increase in +1dBi is a big deal.

Double BiQuad Antenna Calculator




Frequency   MHz λ   cm ED   cm  cm EL   cm Wire Length   cm
RL   cm RH   cm  cm LH   cm Wire diam.   mm Wire area.   mm²

BiQuad Antenna Calculator



Frequency   MHz λ   cm ED   cm  cm EL   cm Wire Length   cm
RL   cm RH   cm  cm LH   cm Wire diam.   mm Wire area.   mm²



 


Parts Required

  • N-Type (female) panel mount connector
  • Reflector - Any metallic sheet like copper or Copper Plated Blank Circuit Board 1.6mm thickness
  • Cable - read this guide before doing anything else: Guide to Antenna Cables & Connectors
    (Very important to choose proper cable! the longer the cable length, the more signal loss you'll have through the cable. Long cable will defeat the purpose of the antenna. Read the guide for more info.)
  • Copper wire for the element.
  • Spacers in each end of the element to hold its position and spacing correct height between the radiator and the reflector. Spacers must be from any non-metallic material. Plastic will do alright.

N-Type (female) connector

Single Sided Copper Clad Board

Building the antenna

I will not show you picture after the picture how to drill the hole in center of reflector. How to use ruler. How to do proper soldering. What kits to use and etc. There are plenty of tutorials for these steps: http://www.ziva-vatra.com/index.php?aid=16&id=SGFyZHdhcmU=, http://martybugs.net/wireless/biquad/ or http://martybugs.net/wireless/biquad/double.cgi
(Note: all calculations in links are for 2.4 GHz WiFi antenna. Use calculator calculated data and measurements for your antenna.)

(Note: Pictures below not to scale)

Element bending


Before you start to bend the wire, make it straight as you can. 
Ensure each side of the element is as straight and symmetrical as possible.
The element sides are rectangular and widths are correct, measured from wire center to wire center. 
The more accurate you do the better as the analysis shows a huge impact in element dimensions.



Mine wire bending technique in the crossing sections.
Note: You must leave a ~1.5 mm gap between the element wires cross overs and solders.

Guidance and recommendations

N-connector in the center of reflector. Maintain correct reflector’s dimensions.


Maintain correct spacing between the element and the reflector!


You must leave approx. 1.5 mm gap between the element wires cross overs and soldered contacts.
Use spacers in each end of the element to strengthen its position and spacing proper height between the radiator and the reflector.
Spacers must be from any non-metallic material.

Finished. Lying on the belly.

Usage

 

This antenna should get the best performance at horizontal polarization.
Note: The antenna is horizontally polarized then reflector is held vertically.




Last updated on 14 Jul 2014

14 comments:

  1. I have HUAWEI E5776 and I need external antenna for frequences
    800, 900, 1800, 2100, 2600 MHz and maybe 2800MHz is good to have too. I do not know all mesurements
    and I am not so good with math.

    ReplyDelete
    Replies
    1. You can use the calculator above

      Delete
  2. very nice project sir. i need one help can send me the detail theoritical calculation to find ED,D,Wire length etc

    ReplyDelete
  3. Isn't the connection flawed?

    The outside braid(shield) of the coaxial is there is keep the centre core coppers energy from escaping out and preventing outside noise interference reaching the core. The braid must shield the core till it reaches the actual transmission part of the hardware . I don't understand why you soldered the end of the copper quad to the shield. Both core and shield are shorting at the quad.

    ReplyDelete
    Replies
    1. The lengthening are 90 degrees out of polarization from the signal received. A Site Masters SA2500EX would be necessary, or use 2nec4.exe antenna modeling software instead. I would target on transmission line. In commercial application Lmr-600 minimum Lmr-1200 at best. Recommended of Lmr-400

      Delete
  4. is it possible to have RH (or any other variables) as a constant figure? my resource is limited to a long and narrow (16.5cm wide) sheet metal. also, i am not able to find calculatior for the version without the lips - is it (lips) a critical part of this antenna measurement? thank you for inspiring me to build my own antenna!

    ReplyDelete
    Replies
    1. Hey Charlie, the only constant figure here is calculated to Frequency. You could use 4nec2 software to make Frequency and RH as constants and look for other variables for best results, but it doesn't worth a fuss. Save your time and do antenna with what ever you got, you will still gain a lot of it even with a huge inaccuracies. as i said before, this antenna type is very forgivable. so no LIPS are not critical part of it. Hope this helps, good luck !

      Delete
  5. the calculator produce wire diameter 4.99mm that would be quite hard to find. can i use copper tubing instead? or maybe 7strands of wire?

    ReplyDelete
    Replies
    1. You probably doing one for very low freq, not sure if biquad is best option for 500mhz but you can try the thickest wire you got, should work.

      Delete
  6. Hi. I had build 2100mHz and 2600mHz double biquad antenna (without lips) using your guide for 3G & 4G respectively. tested it in countryside, WORKS GREAT!!!
    I was wondering if you can prepare a calculator for calculating this antenna without lips. I find it easier to build an antenna without the lips. THANKS!!

    ReplyDelete
    Replies
    1. Hey Raymond, i am pretty sure same measurements will work well for both type biquads.

      Delete
  7. Thanks I've built a few of these Bi-Quad antennas now from the calculator on this website.
    Every single one of them give me good performance! I usually get about 100m range from a WIFI dongle to the router.
    I think with 2 of these antennas pointing to each other I'm sure 200m is achievable

    ReplyDelete
  8. Hi, I wanna know for the lips effect, its said to avoid rear lobe radiation, and on the figures provided its seem for the HORIZONTAL PLANE (Vertical pol.) position, what if i want to fix the antenna as a HORIZONTAL POLARIZATION (Vertical Plane)? should i bend the RL to make lips? how length? same as LH? and what we do on LH?

    ReplyDelete
  9. This comment has been removed by a blog administrator.

    ReplyDelete