Loop Yagi Uda for 23cm (1296MHZ)

[eco32 21]

Before simulating and building the antenna, I wont to learn something about the principles of selecting elements.
I have two booms of 2m each and 40 printed insulated supports for  antenna.
 

I assume that it will be possible to achieve more gain from loop antennas than from traditional Yagi Uda.

sources:

[1] Balanik Antenna Theory (2th)- 10.3.4 Yagi-Uda Array of Loops - page 597

Ina numerical parametric study of coaxial Yagi-Uda arrays of circular loops [37] of
2 to 10 directors, it has beenfoun d that the optimum parameters for maximum forward
gain were

1. circumference of feeder 2πb2      1.1λ, where b2 is its radius. This radius was
chosen so that the input impedance for an isolated element is purely resistive.
2. circumference of the reflector 2πb1      1.05λ, where b1 is its radius. The size of
the reflector does not strongly influence the forward gain but has a major effect
on the backward gain and input impedance.
3. feeder–reflector spacing of about 0.1λ. Because it has negligible effect on the forward
gain, it can be used to control the backward gain and/or the input impedance.
4. circumference of directors 2πb      0.7λ, where b is the radius of any director and
it was chosento be the same for all. Whenthe circumference approached a value
of one wavelength, the array exhibited its cutoff properties.
5. spacing of directors of about 0.25λ, and it was uniform for all.

[2] NTMS 12' (45 Element) And 6' (25 Element) 1296 MHz Loop Yagi Club Project 1979 (I haven't found anything newer)

https://pdf4pro.com/view/1296-loop-yagi-dimensions-ntms-1a4d92.html

 

 

Elements Length
R1-R2 10.23”
DE (brass) 9.59”
D1-D11 8.81”
D12-D17 8.55”
D18-D25 8.25”
D26-D42 8.25”

[3] Efficient Modeling of Radiation and Scattering for a Large Array of Loops

https://www.researchgate.net/publication/224096495_Efficient_Modeling_of_Radiation_and_Scattering_for_a_Large_Array_of_Loops

 

 

 

Edited November 2, 2023 by eco32

[eco32 21]

additional materials

[4] A Parasitic End-Fire Array of Circular Loop Elements

[5] Optimum Design of Yagi Array of Loop

Optimum Design of Yagi Array of Loop.pdf

A Parasitic End-Fire Array of.pdf

[Admin 2426]

,,,and what you want...???
,,,do a simulation ...??

[Admin 2426]

,,,yes, but it seems to me that the gain is too small for an antenna with so many elements...!!!

[eco32 21]

1 hour ago, Admin said:

,,,yes, but it seems to me that the gain is too small for an antenna with so many elements...!!!

It looks like my 90cm quassi dish (grid from 5GHz grid antenna) with dipole feed with coaxial splited balun has biger gain ans smaller dimeters

Looks like 17dBi gain in loop is a naive wish of the author.  Let me try.

I have CST studio for a short time, I don't know how to use yet. Please be kind and share this model, I will try to change the diameters of the elements and distances one by one

 

[Admin 2426]

,,,loop yagi 21 rings...

 

[eco32 21]

41 minutes ago, Admin said:

,,,loop yagi 21 rings...

 

loop yagi 1296mhz.cst

Thank You!

This will help me a lot

[clanon 215]

REFLECTOR SIZE ! (and SHAPE) that's where the 17 dbi come from...

 

[Admin 2426]

 ,,,2 coupled grid parabolic antenna (600x800mm)...!!!

[eco32 21]

5 hours ago, Admin said:

 ,,,2 coupled grid parabolic antenna (600x800mm)...!!!

No, We all know it was stupid idea.  (Bad shape)

 

 

 

6 hours ago, clanon said:

REFLECTOR SIZE ! (and SHAPE) that's where the 17 dbi come from...

 

 

 

It is based on Pacyfic Grid 917x720 and 15cm deep 5.6GHz grid antenna symulation + Yagi Uda in revers - directors works likea rediators (This is not a good representation, Matlab has big limitations)

1296MHZ => 17.3dBi

oryginal grid antenna https://www.cyberbajt.pl/produkt/350/pacific-grid-56-ghz28-dbi.html

 

[eco32 21]

Lets continnue long hi gain Yagi for a 1296MHZ (it may by scaled for LTE or WIFI), these publications look better than those I pasted earlier [1-5]

[6] Randy, K9BCT he build Hybrid Biquod for EME, 2x200cm boom and 19dBi (extended version of biqoud hybrid Yagi DL7KM)

https://www.dcarc.club/presentations/2019-03-05 High Gain 70CM Loop Fed Array and 23cm BiQuadYagi’s by K9BCT.pdf

 

 

"47 element version (44 directors, 2 loop DE and reflector) has a version (44 directors, 2 loop DE and reflector) has a relatively impressive frontal pattern with over 19dbi relatively impressive frontal pattern with over 19dbi"

 

other parameters:

F/B, almost 34db.

G=19.17 dBi

TA=31.5 K

Tloss=3.0

K=3.0 K

G/T=+4.20 dB..

Impedance is 49.--0.162j ohms

 

[7] - International Microwave Handbook  -  (I have only few pages, if someone has full book, please share before i will buy )

 

it looks like You can not achive more dBi than on this chart will let You. (BTW Antenna from [7] biqod hybrod Yagi 2x200cm boom 19dBi looks good

[Admin 2426]

,,,too much noise for nothing...!!!!

Closed topic!!!