Subject: Is it possible to use Flat spiral Bifilar coils in RF Antenna Circuits ?

Tesla applied in 1893 for a patent on an electrical coil which is his "Coil for 
Electro-magnets,", patent number 512,340. It is a curious design because, 
unlike an ordinary coil made by turning wire on a tube form, this one uses two 
wires laid next to each other on a planar form but with the end of the first 
one connected to the beginning of the second one.

The Bifilar windings (Tesla type) are coiled in two forms :
a- Bifilar coil in solenoidal shape (3 dimensional structure wound on 
cylindrical style)
b- Bifilar coil in flat spiral shape (planar shape, which is called as Flat 
spiral coil)

My questions are :

1- What are the differences of the physical properties between a flat spiral 
Bifilar coil and solenoidal shaped Bifilar coil ?

2- According to question (1) which type of Bifilar coil is better to use ?

3- Is it possible to use a Tesla type bifilar winding in a LC (tank) circuit, 
which interesting results do you expect to get if used in two different styles ?

4- Is it possible to use Tesla type bifilar winding in an RF antenna, which 
interesting results do you expect to get if used in two different styles ?

5- What happens if a Tesla type bifilar winding is used in a transformer ?

Main Reference
1- http://www.keelynet.com/tesla/
2- http://www.tfcbooks.com/patents/coil.htm

Re: Is it possible to use Flat spiral Bifilar coils in RF Antenna Circuits ?