50 / 430MHz Slim Hentenna by JA1HWO
The structure of the hentena is a vertically long loop, which is characterized by moving and adjusting the power supply for matching.
http://mk1502.web.fc2.com/ahv6/6shente.htm

50MHz "SKYDOOR" JA1HWO Original Antenna by JA1HWO
The SKYDOOR is 6m band antenna. It is 1 loop simple Antenna.
This site is mainly in Japanese language, but the pictures speak for themselves.
http://mk1502.web.fc2.com/ap02/6skydoor.htm

by JA1HWO
This antenna is a "magnetic field antenna" with a structure that has a feeding part in the center and a resonance part on the outside as shown in the photo by electromagnetic coupling.
http://mk1502.web.fc2.com/ahv6/6ml.htm

50MHz squalo antenna by JA1HWO
A dipole that is bent horizontally and made into a square is called a square antenna from its shape. Previously it was quite popular as a 50MHz antenna, so you may know who has an old call.
http://mk1502.web.fc2.com/ahv6/6sq.htm

6 Meter Rotatable Delta Loop by KK5ID
The 6 Meter Band may be dead at times, but help bring it to life with Larry's rotatable loop project. Simple, easy to build and won't break the bank.
http://www.hamuniverse.com/kk5iddelta.html

6 Meters Small Magnetic Loop by PY1AHD
The 6 meters loop is made with a section of 1 meter 70 centimeters, 9 mms. soft copper tube closed by a 10 Pico farads mini butterfly capacitor.
This loop was designed to be used with a QRP transceiver like the Yaesu FT 817 or the Icom IC 703.
http://www.alexloop.com/artigo31.html

A Hentenna for 6 Meters by JR1LZK
The antenna called Hentena has many variations. Interest was stimulated by JH1FCZ and sites that deal with anomalous hentenna.
http://lzk.cocolog-nifty.com/mt/2007/08/1_d72f.html
 

Einfach aufzubauende Deltaloop für 50MHz (6m) durch DL5DBM
Ich habe diese Antenne auf dem Dachboden aufgebaut, und in dieser Form im Gebälk aufgehangen (Unterdach).
https://www.qsl.net/dl5dbm/Deltaloop-6m/dl6m_d.pdf
 

Hentenna for the 6m band by DL1GSJ
My impression is, that the Hentenna performs better than my commercial Al-pipe dipole. Moreover it is easier to transport and/or store anyway.
https://www.qsl.net/dl1gsj/html/hentenna.html

The Hentenna Re-visited by W8NSI
The antenna has good performance and many advantages and it has become very popular in Japan. Many JA stations make it and enjoy it at home or in the field.
http://www.hamuniverse.com/hentenna.html