Scanable Sparse Antenna Array

• US 20070273603A1
• Filed: 11/27/2003
• Published: 11/29/2007
• Est. Priority Date: 11/27/2003
• Status: Active Grant

• Current Assignee: Optis Cellular Technology LLC (Brevet Capital)
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Falk, Kent, Svensson, Bengt, Engstrom, Ulrika
• Granted Patent: US 7,696,945 B2
• Time in Patent Office: Days
• US Class Current: 343/844
• CPC Class Codes: H01Q 1/523 between antennas of an array
• CPC Class Codes: H01Q 1/525 between emitting and receiving antennas
• CPC Class Codes: H01Q 13/22 Longitudinal slot in boundary wall of waveguide or transmission line H01Q13/203 takes precedence
• CPC Class Codes: H01Q 21/005 Slotted waveguides arrays
• CPC Class Codes: H01Q 3/30 varying the relative phase between the radiating elements of an array H01Q3/2605, H01Q3/2658, H01Q3/2682, H01Q3/44 take precedence

Abstract

A sparse array antenna is disclosed. The antenna comprises series-fed antenna array columns tuned to a respective transmit and receive frequency. The transmitting and receiving radiation elements are formed with a given distance between each transmitting radiator element and each receiving radiator element, and the series-fed antenna columns are arranged in parallel, perpendicular to a symmetry line forming a symmetric interleaved transmit/receive array. Furthermore the receiving array columns operate as parasitic elements in a transmit mode and transmitting array columns operate as a parasitic elements in a receive mode, thereby reducing creation of grating lobes. The created sparse array antenna may further be arranged to be scanable to also provide reduced sidelobes entering visual space when scanning the main radiation lobe from an off boresight direction. Typically the series-fed array columns may be formed as extended ridged slotted wave-guides tuned to a respective transmitting or receiving frequency.

Claims

1. A sparse array antenna comprising series-fed antenna array columns tuned to a respective transmit and receive frequency, wherein

transmitting and receiving array columns are formed with a given distance between each transmitting radiator element and each receiving radiator element, the series-fed antenna columns being arranged in parallel to each other, thereby forming a symmetric interleaved transmit/receive array;

and

receiving array columns operate as parasitic elements in a transmit mode and transmitting array columns operate as parasitic elements in a receive mode, thereby reducing creation of grating lobes.

2. The antenna according to claim 1, wherein a distance between each transmitting antenna array column and each receiving antenna array column is typically increased to be of an order of one wavelength (λ

) to thereby obtain a sparse array.

3. The antenna according to claim 2, wherein the series-fed array columns are formed as extended ridged slotted wave-guides tuned to a respective transmitting and receiving frequency.

4. The antenna according to claim 3, wherein when having number n of slots in each slotted transmitting wave-guide the number of slots in each slotted receiving wave-guide being generally n±

x, where x represents an integer digit (x=0, 1, 2,3 . . . ).

5. The antenna according to claim 2, wherein the series-fed array columns are formed as extended transmission lines containing radiation elements, the array columns being tuned to a respective transmitting and receiving frequency.

6. The antenna according to claim 1, wherein the sparse array antenna is arranged to be scanable to also provide reduced sidelobes entering visual space when scanning the main radiation lobe from an off boresight direction.

7. The antenna according to claim 1, wherein each one of the series-fed antenna column is narrowly tuned within a respective frequency band to thereby reduce coupling between the transmitting and receiving bands used.

8. The antenna according to claim 1, wherein the series-fed antenna array columns are connected to and fed from an active receive/transmit (T/R) module.

9. The antenna according to claim 2, wherein only one set of series-fed columns being actively used and another interleaved set of series-fed columns are terminated by a suitable load forming parasitic columns of the sparse array antenna.