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Browse Prior Art Database

Printed Dipole with Printed Balun

IP.com Disclosure Number: IPCOM000118751D
Original Publication Date: 1997-Jun-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 4 page(s) / 163K

Publishing Venue

IBM

Related People

Canora, FJ: AUTHOR [+2]

Abstract

Disclosed is an invention which provides a compact, planar, readily manufactured balun and antenna structure, having a form factor substantially improved over the related art. The form factor of the present invention is such that it can be embedded inside many devices, such as cordless phones and handheld computers and computer mouses, and still exhibit near-omnidirectional radiation. More particularly, the present invention includes a novel arrangement and combination of a tapered balun circuit and dipole antenna, each formed of planar conductors disposed on a flat substrate.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 37% of the total text.

Printed Dipole with Printed Balun

      Disclosed is an invention which provides a compact, planar,
readily manufactured balun and antenna structure, having a form
factor substantially improved over the related art.  The form factor
of the present invention is such that it can be embedded inside many
devices, such as cordless phones and handheld computers and computer
mouses, and still exhibit near-omnidirectional radiation.  More
particularly, the present invention includes a novel arrangement and
combination of a tapered balun circuit and dipole antenna, each
formed of planar conductors disposed on a flat substrate.

      The printed dipole antenna and printed balun circuit is formed
of planar conductors disposed on a printed circuit board.  The
printed balun circuit is a linear taper circuit with one balun line
having a different taper than the other balun line.  The different
tapers provide a balanced impedance looking from the dipole feed
point toward a coaxial cable connected to the other end of the balun
lines.  The tapered balun is formed of two planar conductors disposed
on the substrate, each having a tapered portion, the specific taper
of one being different from the taper of the other.  Also disposed on
the substrate is a dipole antenna formed of a pair of matching flat
conductors, each being one quarter the wavelength of the signal to be
radiated.  The differing tapers of the respective balun conductors
effects a correspondingly different current density from one balun
conductor to the other.  The differing current density obtains the
balun's function of matching the unbalanced feed line to the balanced
dipole antenna.  The planar balun conductors can be disposed on the
same flat substrate as the dipole antenna.

      Fig. 1 shows is a top elevation view of a first embodiment of
the invention, with conducting bars of a dipole and an associated
balun conductor formed on the top and bottom substrate surface,
respectively.  Fig. 2 shows a bottom elevation view of the embodiment
of Fig. 1.  Fig. 3 shows a front elevation view of the embodiment of
Fig. 1 with a connector.  Referring to Figs. 1-3, there is a
supporting substrate (1) having a top surface (2) and a bottom
surface (4).  The supporting substrate (1) has thickness (D) and is
made, according to general printed circuit board practice, of a
dielectric material such as GETEK, DUROID, TEFLON, or equivalent
materials.  The thickness (D) is determined by the size and
structural constraints of the housing (not shown) in which the
present invention is mounted.  As can be readily seen by one of
skill, the remaining dimensions of the embodiments described herein
can be adjusted corresponding to the particular thickness (D).  The
outer dimensions of the substrate, shown as SL and SW, are not
critical and are set in accordance with the dimensions of the
circuitry described below that is disposed thereon.

      Referring to Fig. 1, a planar dipole cond...