Microwave Sensor

• US 20080165002A1
• Filed: 12/26/2005
• Published: 07/10/2008
• Est. Priority Date: 01/07/2005
• Status: Abandoned Application

• Current Assignee: Optex Company Limited (OPTEX GROUP Co., Ltd.)
• Original Assignee: Optex Company Limited (OPTEX GROUP Co., Ltd.)
• Inventors: Tsuji, Masatoshi
• Application Number:
  US11/794,597
• Publication Number:
  US 20080165002A1
• Time in Patent Office: Days
• US Class Current: 340/552
• CPC Class Codes: G01S 13/04 Systems determining presence of a target based on relative movement of target G01S13/56
• CPC Class Codes: G01S 7/40 Means for monitoring or calibrating
• CPC Class Codes: G01V 3/12 operating with electromagnetic waves operating with millimetre waves G01V8/005
• CPC Class Codes: G08B 13/2491 Intrusion detection systems, i.e. where the body of an intruder causes the interference with the electromagnetic field

Abstract

According to one embodiment, a microwave sensor includes: a first directional coupler (DC1) connected on a path of a transmission antenna unit (A1); a second directional coupler (DC2) connected on a path of a reception antenna unit (A2), and a determination unit (4) that obtains, based on monitor outputs from these, a scattering parameter S₁₁ corresponding to a reflectance property at the transmission antenna unit (A1) and a scattering parameter S₂₁ corresponding to a transmission property from the transmission antenna unit (A1) to the reception antenna unit (A2), and outputs an alarm signal (Dout2) when at least one of the scattering parameter S₁₁ and the scattering parameter S₂₁ continuously exhibits a value outside its respective pre-set range over a predetermined period of time.

Claims

1. A microwave sensor that transmits microwaves toward a detection area from a transmission antenna unit, receives reflected waves of the microwaves reflected by an object present in the detection area at a reception antenna unit, and carries out an object detection operation based on the received reflected waves, the microwave sensor comprising:

a first directional coupler connected on a path of the transmission antenna unit;

a second directional coupler connected on a path of the reception antenna unit, and

a determination unit that obtains, based on monitor outputs from the first directional coupler and the second directional coupler, a scattering parameter S₁₁ corresponding to a reflectance property at the transmission antenna unit and a scattering parameter S₂₁ corresponding to a transmission property from the transmission antenna unit to the reception antenna unit, and outputs an alarm signal when at least one of the scattering parameter S₁₁ and the scattering parameter S₂₁ continuously exhibits a value outside its respective pre-set range over a predetermined period of time.

2. The microwave sensor according to claim 1,

wherein the determination unit outputs the alarm signal when an absolute value of the scattering parameter S₁₁ is not less than a first reference value, or when an absolute value of the scattering parameter S₂₁ is not less than a second reference value.

3. The microwave sensor according to claim 1,

wherein the determination unit monitors the scattering parameter S₁₁ as a vector value, and outputs the alarm signal when the scattering parameter S₁₁ falls outside a pre-set region.