Communications: radio wave antennas – Antennas – With coupling network or impedance in the leadin
Reexamination Certificate
2001-02-21
2001-10-23
Phan, Tho G. (Department: 2821)
Communications: radio wave antennas
Antennas
With coupling network or impedance in the leadin
C343S858000, C343S7000MS, C333S126000, C455S129000
Reexamination Certificate
active
06307525
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the field of diplexing/multiplexing flat panel antennas.
2. Description of the Related Art
The art provides small size patch and microstrip antennas that are generally useful for their limited intended purposes.
However, the need remains in the art for a small, flat, thin, multiband, high-frequency antenna that can be manufactured as a stand-alone assembly, or that can be integrated into a mobile or a fixed position wireless communication device, wherein a transmission line multiplexer, such as a microstrip diplexer/multiplexer or a stripline diplexer, functions as a frequency responsive routing network that automatically routes a given high frequency to a matching antenna element in accordance with the frequency of the high frequency.
SUMMARY OF THE INVENTION
The present invention provides a small, indoor/outdoor, shock tolerant, flat panel, multiband, diplexing/multiplexing, transmit/receive antenna.
More specifically, this invention provides a flat panel diplexing/multiplexing antenna. In diplexing embodiments of the invention a diplexing antenna is provided having a flat dielectric substrate member on one side of which is disposed a planar metal transmission line network, such as a microstrip transmission line network or a stripline transmission line network, that connects one input/output port to a first and a second antenna port. A first metal antenna element is connected to the first antenna port, and a second metal antenna is connected to the second antenna port. A continuous metal sheet is disposed on the other side of the substrate member so as to underlie only the transmission line network. The transmission line network and its overlying metal sheet form a microstrip-type diplexer that automatically provides a low-impedance-route (i.e., a matched or 50 ohm route) between the input/output port and a first antenna at one frequency, or frequency range, as the microstrip-type diplexer concomitantly provides a second high impedance route (i.e., a mismatched route) between the input/output port and the second antenna at this one frequency or frequency range. In this manner, energy at this one frequency or frequency range is automatically directed to the first antenna, as substantially none of the energy at this one frequency or frequency range is directed to the second antenna. In this same device, when a different frequency or frequency range is provided to the input/output port, energy at this different frequency or frequency range is automatically directed to the second antenna, as substantially none of the energy at this different frequency or frequency range is directed to the first antenna.
Thus, the diplexing/multiplexing antenna of the invention operates at the one frequency or frequency range, at the different frequency or frequency range, or at both the one frequency or frequency range and the different frequency or frequency range, all without physical switching being required.
In a preferred embodiment of an antenna in accordance with this invention, a unitary construction is formed on a flat and planar copper clad and low loss dielectric substrate; for example, a substrate that is made from a phenolic resin.
The substrate is quite thin and is generally rectangular, or perhaps square, in its top and bottom profile views. The substrate includes a first flat side, a second flat side that is generally parallel to the first flat side, and four edge portions that form the four rectangular, or square boarders or edges of the substrate.
An input/output port or terminal is provided on an edge of the substrate, or by means of a connection directly to the input/output port of the diplexer/multiplexer antenna.
In one embodiment of the invention, at least two physically spaced antenna ports are also provided on the edges of the substrate. In this embodiment of the invention, an antenna element is cable-connected to each of the antenna ports.
In another embodiment of the invention, at least two antenna ports are located on the one side of the substrate so as to be spaced from the substrate edges. In this embodiment of the invention triangular shaped, or pseudo triangular shaped, metal or copper antenna elements, each having an apex and a base, are also located on this one side of the substrate, and the triangle apex of each antenna element is formed integrally with a metal antenna port.
A metal or copper transmission line conductor pattern, such as a microstrip conductor pattern or a stripline conductor pattern, is also located on this one side of the substrate to form a transmission line network that connects each of the antenna ports to the input/output port. In an embodiment of the invention, the input/output port was a 50 ohm port.
The transmission line diplexer/multiplexer construction and arrangement is defined by a metal conductor pattern that lies on this one side of the substrate.
When the transmission line diplexer/multiplexer is a microstrip diplexer/multiplexer, a metal sheet on the other side of the substrate is provided to underlie only the metal conductor pattern, and one conductor of a feed line is connected to the input/output port as the other conductor of the feed line is connected to the metal sheet.
When the transmission line diplexer/multiplexer is a stripline diplexer/multiplexer, a second metal sheet is provided to be insulated from and to overlie only the metal conductor pattern. In this diplexer/multiplexer, the second metal sheet is electrically connected to the first metal sheet.
The transmission line diplexer/multiplexer operates such that when a given high or MHz frequency (such as 860 MHz having utility in cellular analog local telephone service) is applied to the input/output port, a matched or 50 ohm impedance path exists between the input/output port and a first antenna port, whereas the impedance path that the transmission line diplexer/multiplexer presents relative to all other antenna ports is mismatched and so far from 50 ohms that all other antenna ports are isolated from the given high or MHz frequency input energy. When a different-frequency is applied to the input/output port, a matched or 50 ohm impedance path exists between the input/output port and a different antenna port, whereas the impedance path that the transmission line diplexer/multiplexer now presents relative to all other antenna ports is mismatched and so far from 50 ohms that all other antenna ports are isolated from the different-frequency input energy.
Each individual metal conductor that is within the transmission line diplexer/multiplexer provides an individual microstrip or stripline conductor. The characteristic impedance and the length of each individual microstrip/stripline conductor is selected to provide the low impedance path to the correct antenna port.
The characteristic impedance of any given microstrip/stripline conductor is a function of (1) the width of the microstrip/stripline conductor (i.e., the dimension that is measured parallel to the underlying substrate surface), and (2) the thickness of the substrate (i.e., the dimension that is measured perpendicular to the underlying substrate surface), with the thickness of the given microstrip/stripline conductor and the thickness of the metal sheet (also called a ground plane) that underlies/overlies the microstrip/stripline conductor element having only a minor affect on the characteristic impedance of the given microstrip/stripline conductor.
A two wire connector, a two wire cable, or a coaxial cable having a metal ground connection or metal sheath and a metal feed conductor is provided. The ground connection is electrically connected to the metal sheet(s) that underlies/overlie the transmission line conductor pattern, whereas the feed conductor is connected to the input/output port.
As a feature of the invention, but without limitation thereto, a method of the invention provides an antenna as above described wherein a thin and planar dielectric substrate member is first formed such that its two parallel and opposing side
Bancroft Randy Cecil
Bateman Blaine Rexel
Munson Robert Eugene
Centurion Wireless Technologies, Inc.
Hancock E. C.
Holland & Hart LLP
Phan Tho G.
Sirr F. A.
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