Slot antenna array using LTCC technology

• US 7,038,622 B2
• Filed: 11/18/2003
• Issued: 05/02/2006
• Est. Priority Date: 03/03/2003
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Seidel, Juergen, Gaier, Stefan, Schmidt, Ewald, Voitlaender, Klaus
• Primary Examiner(s): HO, BINH VAN
• Application Number:
  US10/502,410
• Publication Number:
  US 20050073460A1
• Time in Patent Office: 896 Days
• Field of Search: 343/700.MS, 343/770
• US Class Current: 343/700.0MS
• CPC Class Codes: G01S 7/032 Constructional details for solid-state radar subsystems
• CPC Class Codes: H01Q 1/3233 particular used as part of a sensor or in a security system, e.g. for automotive radar, navigation systems
• 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

Abstract

In order to produce a planar antenna array in a radar sensor with a multitude of microstrip feeder lines and a multitude of coupling slots for emitting microwave energy into open space, which achieves a favorable antenna efficiency when embodied in a planar design using LTCC technology, the invention proposes embodying the feeder lines and the coupling slots in a multilayer ceramic substrate produced by means of the LTCC thick layer technique with an upper and a lower grounded layer, as well as enclosing the feeder lines and the coupling slots with plated-through contacts from the upper grounded layer to the lower one.

Claims

1. A planar antenna array in a radar sensor for detecting objects in the vicinity of a motor vehicle, with a multitude of microstrip feeder lines and a multitude of coupling slots for emittimg microwave energy into open space, characterized in that

the feeder lines and the coupling slots are embodied in a multilayer ceramic substrate produced by means of the Low Temperature Co-fired Ceramic thick layer technique with an upper and a lower grounded layer,

the feeder lines and coupling slots are enclosed by plated-through contacts from the upper grounded layer to the lower one, and

the feeder lines and coupling slots are surrounded at a fixed distance by plated-through contacts, the distance being smaller than a critical distance at which waveguide modes form.

2. The antenna array according to claim 1, wherein the fixed distance lies in the range from approx. 0.01*λ

to approx. 0.1*λ

, where λ

is the wavelength of the microwave radiation emitted.

3. The antenna array according to claim 1, wherein each coupling slot is enclosed by a single-row arrangement of plated-through contacts.

4. The antenna array according to claim 1, wherein each coupling slot is enclosed by a double-row arrangement of plated-through contacts, wherein the two rows are aligned with each other or offset from each other.

5. The antenna array according to claim 1, wherein the distance of the coupling slots from the end of the resonator is essentially (2n−

1)*λ

/4, where λ

is the wavelength of the emitted microwave radiation and n is a natural number.

6. The antenna array according to claim 1, wherein the distance of the coupling slots from the back wall is essentially 2n*λ

/4, where λ

is the wavelength of the microwave radiation emitted and n is a natural number.

7. The antenna array according to claim 1, wherein the plated-through contacts enclose the coupling slots along an essentially rectangular perimeter line, wherein the distance of the coupling slots from the edge of the plated-through contacts is preferably essentially 2n*λ

/4 perpendicular to the slot direction, where λ

is the wavelength of the microwave radiation emitted and n is a natural number.

8. The antenna array according to claim 1, wherein the plated-through contacts enclose the coupling slots along a perimeter line that bulges in the middle of the slots, wherein the distance is greater than 2n*λ

/4 in the middle of the slots and is less than 2n*λ

/4 outside the middle, where λ

is the wavelength of the microwave radiation emitted and n is a natural number.

9. The antenna array according to claim 1, wherein the plated-through contacts enclose the coupling slots along a perimeter line with rounded corners.

10. The antenna array according to claim 1, wherein two rows of plated-through contacts are provided spaced apart from each other by the distance of half a wavelength.