Broadband patch/slot antenna

• US 6,198,437 B1
• Filed: 07/08/1999
• Issued: 03/06/2001
• Est. Priority Date: 07/09/1998
• Status: Expired due to Fees

• Current Assignee: Air Force Government of The United States of America As Represented By The Secretary
• Original Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Inventors: Watson, Paul M., Gupta, Kuldip C.
• Primary Examiner(s): PHAN, THO GIA
• Application Number:
  US09/350,222
• Time in Patent Office: 607 Days
• Field of Search: 343/700.MS, 343/767, 343/770, 343/769, 343/829, 343/846, 343/848, 343/849
• US Class Current: 343/700.0MS
• 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 13/10 Resonant slot antennas
• CPC Class Codes: H01Q 21/064 using horn or slot aerials slotted waveguides arrays H01Q21/005
• CPC Class Codes: H01Q 9/0407 Substantially flat resonant element parallel to ground plane, e.g. patch antenna dipole H01Q9/285; monopole H01Q9/40

Abstract

A broadband microwave coplanar antenna suitable for use in singular antenna or antenna array dispositions in a plurality of military and other present day uses. The disclosed antenna combines desirable characteristic of the patch and slot antenna forms into an arrangement having both patch resonances and slot resonances. These resonances may be individually accessed and either combined in frequency location or dispersed in frequency to accomplish a broadband combination antenna characteristic. Broadband electrical impedance characteristics are also provided in the dispersed resonance arrangement. The antenna includes a coplanar ground plane member disposed surrounding the active patch/slot element with both physical dimensions of the active patch/slot element and spacings from the ground plane element determining the resonances.

Claims

1. Broadband combination patch and slot coplanar microwave antenna apparatus comprising the combination of:

an electrical conductor ground plane member disposed on an electrically insulating planar substrate member;

said ground plane member including a rectangular shaped electrical conductor aperture having orthogonally disposed shorter and longer aperture sides received in a ground plane interior portion;

a coplanar rectangularly shaped electrically conductive patch antenna member received in electrical isolation, with smaller and larger pairs of spacings respectively from said longer and said shorter aperture sides, within said ground plane conductor rectangular aperture on said electrically insulating planar substrate member;

said electrically conductive patch antenna member being characterized by first and second diametrically opposed radiating edge portions, of respective first and second patch antenna electrical resonance frequency characteristics and disposition adjacent respective ground plane conductor shorter aperture sides;

a first electrical slot resonator inclusive of said first electrically conductive patch antenna member first radiating edge, an adjacent ground plane aperture shorter side conductor and an intervening non-conducting exposed substrate area of said larger patch antenna member to ground plane conductor rectangular aperture spacing, said first electrical slot resonator having a first slot antenna electrical resonance frequency characteristic;

a second electrical slot resonator inclusive of said second electrically conductive patch antenna member second radiating edge, an adjacent ground plane aperture shorter side conductor and an intervening non-conducting exposed substrate area of said larger patch antenna member to ground plane conductor rectangular aperture spacing, said second electrical slot resonator having a second slot antenna electrical resonance frequency characteristic;

a transmission line conductor element received within an elongated ground plane void pathway and communicating radio frequency electrical energy among a region peripheral of said ground plane member and said electrically conductive patch antenna member in said rectangular shaped electrical conductor aperture.

2. The broadband combination patch and slot coplanar microwave antenna apparatus of claim 1 wherein said first and second electrically conductive patch antenna member electrical resonance frequency characteristics are of the same electrical resonance frequency.

3. The broadband combination patch and slot coplanar microwave antenna apparatus of claim 2 wherein said first and second electrically conductive patch antenna member same electrical resonance frequency, said first slot antenna electrical resonance frequency and said second slot antenna electrical resonance frequency comprise at least two different resonance frequencies.

4. The broadband combination patch and slot coplanar microwave antenna apparatus of claim 3 wherein said first and second electrically conductive patch antenna member same electrical resonance frequency, said first slot antenna electrical resonance frequency and said second slot antenna electrical resonance frequency comprise three different resonance frequencies.

5. The broadband combination patch and slot coplanar microwave antenna apparatus of claim 4 wherein said first and second electrically conductive patch antenna member same electrical resonance frequency, said patch antenna electrical resonance frequency and said second slot antenna electrical resonance frequency are respectively a lowest microwave frequency, an intermediate microwave frequency and a highest microwave frequency.

6. The broadband combination patch and slot coplanar microwave antenna apparatus of claim 1 wherein said rectangularly shaped electrically conductive patch antenna member is square in shape and has dimensions selected in response to antenna operating frequency.

7. The broadband combination patch and slot coplanar microwave antenna apparatus of claim 6 wherein said ground plane member rectangular shaped electrical conductor aperture has a shorter aperture side width dimension, parallel to said patch antenna radiating edge portion, selected in response to antenna operating frequency.

8. The broadband combination patch and slot coplanar microwave antenna apparatus of claim 7 wherein said antenna has a center frequency and ten decibels down frequencies determined by selectively dispersed resonant frequencies in said electrically conductive patch antenna member and said first and second slot resonators.

9. The broadband combination patch and slot coplanar microwave antenna apparatus of claim 8 wherein said antenna has measured center frequency and ten decibels down frequencies of seven and five one hundredths gigahertz, six and five one hundredths gigahertz and eight and five hundred seventy five thousandths gigahertz respectively.

10. The broadband combination patch and slot coplanar microwave antenna apparatus of claim 1 wherein said transmission line conductor element received within said elongated ground plane void pathway comprises a conductor disposed perpendicular of said first radiating edge portion and connecting with a lengthwise central point of said first radiating edge portion.

11. The broadband combination patch and slot coplanar microwave antenna apparatus of claim 1 wherein said transmission line conductor element is disposed on an opposite side of said electrically insulating planar substrate member with respect to said electrically conductive patch antenna member and is connected with said electrically conductive patch antenna member by a conductor passing through said electrically insulating planar substrate member.

12. The broadband combination patch and slot coplanar microwave antenna apparatus of claim 11 wherein said transmission line comprises a coplanar waveguide line and further including a plurality of conductive via elements connecting one conductor of said transmission line through said electrically insulating planar substrate member with said ground plane member.

13. The broadband combination patch and slot coplanar microwave antenna apparatus of claim 1 wherein said antenna is one of a plurality of similar antennas disposed in a phased array of antennas.

14. The method of fabricating a broadband planar microwave antenna comprising the steps of:

tuning physical dimensions of a coplanar ground plane-surrounded rectangular patch antenna element portion of said coplanar microwave antenna to resonate at patch antenna first resonant frequencies within an operating frequency band selected for said coplanar microwave antenna;

said tuning step achieving first and second rectangular patch antenna element radiating edge portions of tuning-selected length on opposed sides of said rectangular patch antenna element portion;

attuning different physical spacings, disposed coplanar with and intermediate each of said first and second rectangular patch antenna element radiating edge portions and paralleling adjacent ground plane edge portions, and forming two slot antenna having second and third resonant frequencies, frequencies within said operating frequency band selected for said coplanar microwave antenna;

connecting a transmission line radio frequency energy-conveyance conductor to a central portion of said ground plane-surrounded rectangular patch antenna element radiating edge portion.

15. The method of fabricating a broadband planar microwave antenna of claim 14 wherein said transmission line radio frequency energy-conveyance conductor connects with said rectangular patch antenna element radiating edge portion and comprises physical dimensions generating, within said operating frequency band, a relatively low, coaxial transmission line-compatible, input impedance at an energy input end thereof.

16. The method of fabricating a broadband planar microwave antenna of claim 14 further including the step of selecting physical dimensions for portions of said rectangular patch antenna element intermediate said radiating edge portions, adjacent portions of said ground plane and spacings intermediate thereto for efficient radio frequency energy transmission intermediate said radiating edge portions.

17. Combination patch element and slot element coplanar microwave antenna apparatus comprising the combination of:

a patch antenna element of orthogonal sides, approximately half wavelength physical dimensions and dual opposed extremity radiating edges disposed on a coplanar element plane within a surrounding coplanar ground plane member void;

first and second slot antenna conductor-absence regions, also of approximately half wavelength physical dimension along a greatest length thereof, disposed intermediate each of said opposed extremity radiating edges of said patch antenna element and adjacent ground plane member edges on said co-planar element plane;

transmission line conductor and spacing elements of differing spacing element length from said first and second slot antenna conductor absence regions connecting with radio frequency energy input and radio frequency energy output sides of one patch antenna element radiating edge and communicating radio frequency energy to said first radiating edge and thence to said second radiating edge;

electric field vectors formed across said first and second slot antenna conductor-absence regions, extending orthogonal of said slot antenna half wavelength physical dimension, being vectorially additive and supportive of complementing radiation field patterns extending outward from said coplanar elements plane;

electric field vectors formed across said transmission line spacing elements intermediate said patch antenna element radiating edges being vectorially subtractive and non-radiating and non-contributive to said radiation field patterns.

18. The combination patch element and slot element coplanar microwave antenna apparatus of claim 17 wherein said transmission line conductor and spacing elements communicating radio frequency energy to said first radiating edge extend from a peripheral region of said ground plane member into said ground plane member void in coplanar dispose with said patch antenna element, said ground plane and said slot antenna conductor-absence regions.