Monopulse radar system
A monopulse radar system for detecting an azimuth depending upon amplitude difference or phase difference between signals respectively received by plural receiving antennas, includes: a transmitting array antenna and a receiving array antenna each including antenna elements forming an antenna train, at least one antenna switch disposed among the elements of the transmitting array antenna and/or the receiving array antenna, and a switch controller for turning ON/OFF the antenna switch to change an aperture length of the transmitting array antenna and/or the receiving array antenna thereby changing a beam shape thereof. The antenna elements of the transmitting array antenna and the receiving array antenna are formed on a dielectric substrate. A dielectric length between the antenna train formed by the antenna elements and the antenna switch is ½ dielectric wavelength.
1. A monopulse radar system to detect an azimuth depending upon amplitude difference or phase difference between signals respectively received by a plurality of receiving antennas, the monopulse radar system comprising:
a transmitting array antenna including a plurality of antenna elements forming an antenna train;
a receiving array antenna including a plurality of antenna elements forming an antenna train, the receiving array antenna being used for one of a plurality of receiving antennas;
at least one antenna switch disposed among the plurality of antenna elements of at least one of the transmitting array antenna and the receiving array antenna; and
a switch controller for turning ON/OFF said antenna switch to selectively activate said antenna elements so as to change an aperture length of at least one of the transmitting array antenna and the receiving array antenna thereby changing a beam shape of said at least one of the transmitting array antenna and the receiving array antenna,
wherein said plurality of antenna elements of the transmitting array antenna and the receiving array antenna are formed on a dielectric substrate, and
wherein a dielectric length between the antenna train formed by the plurality of antenna elements and the antenna switch included in at least one of the transmitting array antenna and the receiving array antenna is ½ dielectric wavelength.
2. The monopulse radar system according to claim 1 ,
wherein said antenna switch is a MMIC formed on the dielectric substrate.
3. The monopulse radar system according to claim 2 ,
wherein said MMIC is operated by the bias between a grounding line grounded by a via hole, and bias terminal formed on the dielectric substrate.
4. The monopulse radar system according to claim 3 , further comprising:
a power supply part for supplying an electric power to the antenna train included in at least one of the transmitting array antenna and the receiving array antenna,
wherein the grounding line and the power supply part are connected by the short circuit line having ¼ dielectric wavelength in length.
5. The monopulse radar system according to claim 4 ,
wherein the beam shape is changed to a sharp angle/long distance shape or a wide angle/short distance shape by turning ON/OFF said antenna switch via the switch controller.
6. The monopulse radar system according to claim 4 ,
wherein the transmitting array antenna and the receiving array antenna are formed by a common antenna composed of a plurality of antenna elements.
7. The monopulse radar system according to claim 5 ,
wherein the transmitting array antenna and the receiving array antenna are formed by a common antenna composed of a plurality of antenna elements.
8. The monopulse radar system according to claim 4 ,
wherein the switch controller turns ON/OFF said antenna switch periodically.
9. The monopulse radar system according to claim 5 ,
wherein the switch controller turns ON/OFF said antenna switch periodically.
10. The monopulse radar system according to claim 4 ,
wherein the switch controller turns ON/OFF said antenna switch based upon a distance between the monopulse radar system and an object of interest.
11. The monopulse radar system according to claim 5 ,
wherein the switch controller turns ON/OFF said antenna switch based upon a distance between the monopulse radar system and an object of interest.
12. The monopulse radar system according to claim 6 ,
wherein the switch controller turns ON/OFF said antenna switch based upon a distance between the monopulse radar system and an object of interest.
13. A monopulse radar system for a land transportation vehicle to detect an azimuth depending upon amplitude difference or phase difference between signals respectively received by a plurality of receiving antennas, the monopulse radar system comprising:
a transmitting array antenna including a plurality of antenna elements forming an antenna train;
a receiving array antenna including a plurality of antenna elements forming an antenna train, the receiving array antenna being used for one of a plurality of receiving antennas;
at least one antenna switch disposed among the plurality of antenna elements of at least one of the transmitting array antenna and the receiving array antenna; and
a switch controller for turning ON/OFF said antenna switch based upon position information obtained by a position information retrieval system mounted on the vehicle,
wherein said antenna switch is turned ON/OFF to selectively activate said antenna elements so as to change an aperture length of at least one of the transmitting array antenna and the receiving array antenna thereby changing a beam shape of said at least one of the transmitting array antenna and the receiving array antenna,
wherein said a plurality of antenna elements of the transmitting array antenna and the receiving array antenna are formed on a dielectric substrate, and
wherein a dielectric length between the antenna train formed by the plurality of antenna elements and the antenna switch included in at least one of the transmitting array antenna and the receiving array antenna is ½ dielectric wavelength.
14. The monopulse radar system according to claim 13 ,
wherein said antenna switch is a MMIC formed on the dielectric substrate.
15. The monopulse radar system according to claim 14 ,
wherein said MMIC is operated by the bias between a grounding line grounded by a via hole, and bias terminal formed on the dielectric substrate.
16. The monopulse radar system according to claim 15 , further comprising:
a power supply part for supplying an electric power to the antenna train included in at least one of the transmitting array antenna and the receiving array antenna,
wherein the grounding line and the power supply part are connected by the short circuit line having ¼ dielectric wavelength in length.
17. The monopulse radar system according to claim 16 ,
wherein the beam shape is changed to a sharp angle/long distance shape or a wide angle/short distance shape by turning ON/OFF said antenna switch via the switch controller.
18. The monopulse radar system according to claim 16 ,
wherein the transmitting array antenna and the receiving array antenna are formed by a common antenna composed of a plurality of antenna elements.
19. The monopulse radar system according to claim 16 ,
wherein the switch controller turns ON/OFF said antenna switch based upon distance between the land transportation vehicle and an obstacle of interest.
20. The monopulse radar system according to claim 17 ,
wherein the switch controller turns ON/OFF said antenna switch based upon distance between the land transportation vehicle and an obstacle of interest.