Radar apparatus with harmonic attenuator

Patent metadata

Field	Value
Publication number	US-9964639-B2
Application number	US-201314443062-A
Country	US
Kind code	B2
Filing date	Nov 5, 2013
Priority date	Nov 15, 2012
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

A radar apparatus configured to prevent a harmonic generated by a limiter from being transmitted outside is provided. The radar apparatus includes a harmonic processor between a circulator and a limiter. The harmonic processor includes harmonic processing stubs, and a compensation stub. The harmonic processing stubs attenuate the harmonic which is generated when the limiter attenuates a transmission signal passed through the circulator. The compensation stub cancels a change of a susceptance caused by disposing the harmonic processing stubs.

First claim

What is claimed is:

1. A radar apparatus, comprising:
a radar antenna configured to transmit a transmission signal at a target object and receive, as a reception signal, a reflection wave caused by a reflection of the transmission signal off the target object;
a transmission signal generator configured to generate the transmission signal;
a circulator configured to output the transmission signal to the radar antenna, and output the reception signal to a reception system circuit;
a limiter disposed in the reception system circuit and configured to attenuate the signal based on a signal level of the reception signal;
two or more stubs disposed between the circulator and the limiter and configured to attenuate a harmonic of the transmission signal propagating from the limiter to the radar antenna by a transmission line;
a compensation stub that is the transmission line configured to cancel a change in susceptance caused by the two or more stubs;
a reception signal amplifier disposed on a downstream side of the limiter in a propagating direction of the reception signal, and configured to amplify the reception signal; and
an image generator configured to generate a radar image based on the reception signal amplified by the reception signal amplifier, wherein
at least one of the two or more stubs has a short-circuited tip; and
at least one of the two or more stubs has an open-circuited tip.

2. The radar apparatus of claim 1 , wherein the limiter and the one or more filters are formed on a shared substrate.

3. The radar apparatus of claim 1 , wherein the radar apparatus is installed in a ship and detects the target object in a vicinity of the ship.

4. A radar apparatus, comprising:
a radar antenna configured to transmit a transmission signal at a target object and receive, as a reception signal, a reflection wave caused by a reflection of the transmission signal off the target object;
a transmission signal generator configured to generate the transmission signal;
a circulator configured to output the transmission signal to the radar antenna, and output the reception signal to a reception system circuit;
a limiter disposed in the reception system circuit and configured to attenuate the signal based on a signal level of the reception signal;
two or more stubs disposed between the circulator and the limiter and configured to attenuate a harmonic of the transmission signal propagating from the limiter to the radar antenna by a transmission line;
a compensation stub that is the transmission line configured to cancel a change in susceptance caused by the two or more stubs;
a reception signal amplifier disposed on a downstream side of the limiter in a propagating direction of the reception signal, and configured to amplify the reception signal; and
an image generator configured to generate a radar image based on the reception signal amplified by the reception signal amplifier, wherein
at least two of the two or more stubs each have an open-circuited tip.

Assignees

• Furuno Electric Co

Inventors

• Okimoto Takuya
• Ohnishi Yoshifumi

Classifications

• G01S7/285 Primary

  Receivers · CPC title

• G01S7/02

  of systems according to group G01S13/00 · CPC title

• G01S13/89 Primary

  for mapping or imaging · CPC title

• G01S13/04

  Systems determining presence of a target (based on relative movement of target G01S13/56) · CPC title

• G01S13/582

  adapted for simultaneous range and velocity measurements · CPC title