Multiband flat panel antenna providing automatic routing between a plurality of antenna elements and an input/output port

• US 6,307,525 B1
• Filed: 02/21/2001
• Issued: 10/23/2001
• Est. Priority Date: 02/25/2000
• Status: Expired due to Term

• Current Assignee: Laird Connectivity Inc.
• Original Assignee: Centurion Industries Incorporated (Laird Limited)
• Inventors: Bancroft, Randy Cecil, Bateman, Blaine Rexel, Munson, Robert Eugene
• Primary Examiner(s): Phan, Tho G.
• Application Number:
  US09/789,914
• Time in Patent Office: 244 Days
• Field of Search: H01/Q 2.100, 343/700.MS, 343/850, 343/853, 343/852, 343/858, 343/860, 333/126, 333/129, 333/135, 455/127, 455/129, 455/103
• US Class Current: 343/853
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 21/0075 Stripline fed arrays H01Q21/065 takes precedence
• CPC Class Codes: H01Q 21/30 Combinations of separate antenna units operating in different wavebands and connected to a common feeder system
• CPC Class Codes: H01Q 9/0407 Substantially flat resonant element parallel to ground plane, e.g. patch antenna dipole H01Q9/285; monopole H01Q9/40
• CPC Class Codes: H01Q 9/40 Element having extended radiating surface

Abstract

A transmit/receive antenna selectively operates to transmit or receive at one or more of a plurality of different frequencies in the MHz range. A planar transmission line diplexer or multiplexer that is selected from the group microstrip multiplexer diplexer/multiplexer and stripline diplexer/multiplexer connects an input/output port to a plurality of antenna ports that are physically spaced from each other and from the input/output port. One antenna element is connected to each of the antenna ports. The transmission line diplexer/multiplexer includes a plurality of individual microstrip/stripline elements that have a characteristic impedance and a length that are selected such that the transmission line diplexer/multiplexer automatically provides a matched impedance path between a given antenna element and the input/output port when an antenna-matching frequency is received by the given antenna element or when the antenna matching frequency is applied to the input/output port. At the same time, the transmission line diplexer/multiplexer automatically provides a very mismatched impedance path between all others of the antenna elements and the input/output port.

Claims

1. A multiplexing antenna operable at each one of N different frequencies, wherein N is an integer greater than 1, said antenna comprising:

an input port for transmitting/receiving energy at one or more of said N frequencies;

N output ports, said output ports being physically spaced from each other and from said input port;

N antenna elements, each one of said antenna elements being connected to a different one of said N output ports, and each one of said antenna elements being operable at a different one of said N frequencies;

a transmission line multiplexer network selected from the group microstrip transmission line, multiplexer network and stripline transmission line multiplexer network interconnecting said input port and said N output ports;

said transmission line multiplexer network having a plurality of interconnected transmission line elements whose individual characteristic impedance and individual length are selected to provide a matched-impedance path between a given one of said antenna elements and said input port when a corresponding one of said N frequencies for which said given one of said antenna elements is applied to said input port; and

said transmission line multiplexer network concomitantly providing a mismatched-impedance path between all others of said antenna elements and said input port when said corresponding one of said N frequencies is applied to said input port.

2. The antenna of claim 1 wherein said transmission line multiplexer network includes N series-connected metallic transmission line elements that directly connect said input port to each of said N output ports, and at least one metallic transmission line element extending as a dead-end stub from each of said N series-connected metallic transmission line elements.

3. The antenna of claim 1 including:

a first flat dielectric substrate member having a first side that carries a metallic transmission line multiplexer network on a first portion of said first side, and that carries said antenna elements on a second portion of said first side; and

a first metallic sheet element on an opposite side of said substrate member so as to underlie only said metallic transmission line multiplexer network.

4. The antenna of claim 3 including:

a second flat dielectric substrate member having a first generally flat side that carries a second metallic sheet element on one side thereof;

an opposite side of said second substrate member being in physical engagement with said metallic transmission line multiplexer network in a manner to cause said second metallic sheet element to overly only said metallic transmission line multiplexer network.

5. A method of providing a diplexing antenna that is operable at two different frequencies, comprising the steps of:

providing an input port for selectively receiving energy at one or both of said two frequencies;

providing two output ports that are physically spaced each other and from said input port;

providing two antenna elements that are individually operable at one of said two frequencies;

providing a transmission line diplexer that is selected from the group stripline diplexer and microstrip diplexer connecting said input port to each of said two output ports;

said transmission line diplexer providing a matched impedance path to a first of said two antenna elements when a first frequency is applied to said input port, and

said transmission line diplexer concomitantly providing a mismatched impedance path to a second of said two antenna elements.

6. The method of claim 5 including the steps of:

providing said transmission line diplexer as first transmission line portions that directly connect said input port to each of said two output ports; and

providing at least one second transmission line portion that extends as a stub from said first transmission-line portions.

7. A transmit/receive assembly operable to transmit or receive at one or more of a plurality N of different frequencies, comprising:

one input/output port;

a plurality N of antenna ports;

a planar transmission line diplexer/multiplexer selected from the group microstrip diplexer/multiplexer and stripline diplexer/multiplexer connecting said input/output port to each of said plurality of antenna ports;

each of said N antenna ports for transmitting/receiving a unique matching frequency that corresponds to a unique one of said N different frequencies;

said transmission line diplexer/multiplexer including a plurality of microstrip/stripline elements having physical dimensions selected such that said transmission line diplexer/multiplexer provides a matched impedance path between a given antenna port and said input/output port when a matching frequency corresponding to said given antenna port is received by said given antenna port, or when a matching frequency corresponding to said given antenna port is applied to said input/output port; and

said transmission line diplexer/multiplexer concomitantly providing a mismatched impedance path between all others of said antenna ports and said input/output port.

8. The assembly of claim 7 wherein said plurality N of different frequencies is in the MHz or GHz range.

9. The assembly of claim 8 including:

a plurality N of antenna elements;

each of said antenna elements individually connected to a different one of said plurality N of antenna ports; and

each of said antenna elements for receiving/transmitting a unique one of said N different frequencies.

10. An antenna operable at any or all of N different frequencies, comprising:

an input port for transmitting/receiving any or all of said N different frequencies;

N output ports, each of said output ports for operation at a different one of said N different frequencies;

a transmission line network interconnecting said input port and said N output ports;

said transmission line network having a plurality of interconnected transmission line elements whose individual physical dimensions are selected to provide a matched impedance path between a given output port and said input port when one of said N different frequencies for which said given output port is operable applied to said input port; and

said transmission line network concomitantly providing a mismatched impedance path between all others of said output ports and said input port when said one of said frequencies for which said given output port is operable is applied to said input port.

11. The antenna of claim 10 wherein said transmission line network includes a plurality N of series connected metallic transmission line elements that individually connect said input port individual ones of said N output ports, and at least one metallic transmission line element extending as a dead-end stub at least one of said N series-connected metallic transmission line elements.

12. A method of providing an antenna that is operable at N different frequencies, comprising the steps of:

providing an input port for selectively receiving energy at said N different frequencies;

providing N output ports;

providing N antenna elements, each antenna element being operable at a different one of said N different frequencies;

connecting one of said N antenna elements to each of said N output ports to thereby define each output port as an output port that is operable at a corresponding one of said N different frequencies;

providing a transmission line network connecting said input port to each of said N output ports;

said transmission line network providing a matched impedance path to one of said N output ports when a frequency is applied to said input port corresponding to said one output port; and

said transmission line network concomitantly providing a mismatched impedance path to all others of said output ports.

13. The method of claim 12 including the steps of:

providing said transmission line network as N transmission line portions that connect said input port to each of said N output ports; and

providing at least one transmission line portion that extends as a stub from at least one of said N transmission line portions.