Radar head module

A radar head module includes a high-frequency circuit that sends and receives a radar beam for a radar, a case that covers the high-frequency circuit, and a mounting member for attaching the radar head module to an outside body on which the radar head is to be mounted. High-frequency circuits are attached to the mounting member. While a circuit board is attached on sides of the high-frequency circuits and another circuit board is attached on the bottom of the high-frequency circuits, the case is attached to the mounting member. The characteristic adjustment of the radar is performed by attaching a supporting portion of the mounting member to the frame before the case is covered thereon, and then the case is attached to the mounting member.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a radar head module such as a vehicle-mounted EHF (extremely high frequency) radar and a characteristic adjustment method thereof.

2. Description of the Related Art

Japanese PCT Patent Publication No. 2000-508874 discloses microwave and millimeter-wave radars suitable for being vehicle-mounted. In a radar head module shown in this Publication, in order to effectively utilize a space between a primary radiator and a dielectric lens, a circuit board is arranged between the primary radiator and the dielectric lens and a notch for passing electromagnetic waves is formed on the circuit board.

However, in the radar head module shown in the Publication, a rectangular circuit board used generally is difficult to be utilized, thereby increasing cost. Since the circuit board is arranged on the back bottom of a box-like case, efficiency of assembling is low and manufacturing cost is increased. Furthermore, since the circuit board is attached to the case, the module cannot be operated as a radar head in a state in which the case is removed, so that characteristics of the radar head module cannot be absolutely adjusted in a state in which the case of the radar head module is attached at a predetermined position of a vehicle with the case removed.

SUMMARY OF THE INVENTION

In order to overcome the problems described above, preferred embodiments of the present invention provide a radar head module which is miniaturized and reduced in cost, and a characteristic adjusting method thereof.

A radar head module according to a preferred embodiment of the present invention includes a high-frequency circuit that sends and receives a radar beam for a radar, a case that covers the high-frequency circuit, and a mounting member for attaching the radar head module to an outside body, wherein the high-frequency circuit and the case are attached to the mounting member.

Preferably, the high-frequency circuit includes a primary radiator for sending and receiving the radar beam, and the mounting member includes a dielectric lens attached thereto and having a focal plane formed substantially at the position of the primary radiator.

Preferably, the high-frequency circuit includes a plurality of circuit boards constituting peripheral circuits of the high-frequency circuit, the plurality of circuit boards being arranged along the bottom and sides of the high-frequency circuit.

Preferably, circuit boards arranged on sides of the high-frequency circuit of the plurality of circuit boards are positioned at the back of the dielectric lens.

Preferably, the plurality of circuit boards are connected to each other with flexible substrates.

Preferably, a portion of the case is provided with a section that is thermally connected to a heat generating section of the high-frequency circuit.

Preferably, according to a preferred embodiment of the present invention, the case has a box-like shape with one open surface, and wherein the high-frequency circuit is shielded by the case, the mounting member, and the dielectric lens in a state in which the open surface is attached to the mounting member.

According to yet another preferred embodiment of the present invention, a method for adjusting characteristics of a radar head module having any one of the structures described above includes the steps of attaching the mounting member to the body to be mounted in a state in which members of the radar head module other than the case are attached to the mounting member, and performing characteristic adjustment.

According to another preferred embodiment of the present invention, the high-frequency circuit and the case are attached to the mounting member for attaching the radar head module to an outside body, so that a normal rectangular circuit board can be used. Also, an operation to attach the high-frequency circuit to the depth of the case is eliminated, thus facilitating and simplifying the assembly process. Furthermore, even when the case is not attached to the mounting member, the radar head module functions, extremely facilitating characteristic adjustment.

Also, the dielectric lens may be also attached to the mounting member, so that the positional relationship between the primary radiator of the high-frequency circuit and the dielectric lens can be accurately set, thus minimizing the effect due to assembly accuracies.

According to a preferred embodiment of the present invention, the plurality of circuit boards constituting peripheral circuits of the high-frequency circuit may be arranged along the bottom and sides of the high-frequency circuit, so that the circuit boards constituting peripheral circuits, which are not required to have the high relative positional-accuracies, can be positioned at a dead space, miniaturizing the entire projector.

In the plurality of circuit boards, the circuit boards arranged on sides of the high-frequency circuit may be positioned at the back of the dielectric lens, so that a space between the dielectric lens and the high-frequency circuit can be efficiently utilized, miniaturizing the entire projector that much.

The circuit boards may be connected to each other with flexible substrates, so that the plurality of circuit boards can be positioned within a small space within the case at a high degree of freedom.

A portion of the case may be provided with a section thermally connecting to a heat generating section of the high-frequency circuit, so that the heat produced in the high-frequency circuit is radiated while the entire projector is miniaturized, thus obtaining stable characteristics under wide-range temperature circumstances.

The high-frequency circuit may be shielded with the case, the mounting member, and the dielectric lens, so that dust-proof and water-proof characteristics thereof can be readily increased, increasing environment resistance.

Also, by attaching the mounting member to the body to be mounted before the case is attached thereto, and then by performing characteristic adjustment, predetermined characteristics under circumstances, in which the module is practically used, can be readily performed.

Other features, elements, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments thereof with reference to the attached drawings.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A structure of a radar head module according to a preferred embodiment of the present invention will be described with reference toFIGS. 1to3.

FIG. 1is an exploded view of the radar head module;FIG. 2is a sectional view of the radar head module in an assembled state and attached to a body to be mounted.

Referring toFIG. 1, a mounting member10is a member to be mounted by various members, which will be described later, for attaching them to the body to be mounted, such as a vehicle. Numerals1and2denote a high-frequency wave circuit (a high-frequency wave block). A circuit board3arranged on the bottom of the high-frequency wave circuit1and circuit boards4arranged on sides of the high-frequency wave circuits1and2constitute peripheral circuits of the high-frequency wave circuit. InFIG. 1, only one circuit board4on the side is shown and the other opposing it is omitted for brevity. A dielectric lens5is attached on the front surface of the mounting member10. A lens cover6is for provided fixing the dielectric lens5to the mounting member10.

A case11has a box-like shape with one open surface to be attached to the mounting member10. The case11is attached to the mounting member10in a state in which the high-frequency wave circuits1and2and the circuit boards3and4are attached to the mounting member10, so as to surround these circuits and circuit boards. The case11, the dielectric lens5, and the lens cover6seal the internal high-frequency wave circuits1and2and the circuit boards3and4.

Referring toFIG. 2, numeral20denotes a frame of the body on which the radar is to be mounted, such as a vehicle and numeral10adenotes a supporting portion for supporting the mounting member10to the frame20with a bolt.

Numeral10bdenotes projections of the mounting member10. The high-frequency wave circuit1is fixed to the projections10bwith screws in a state abutted to the projections10b. The high-frequency wave circuit1is provided with a primary radiator8. The size of the projections10bis determined so that the primary radiator8is positioned on a focal plane of the dielectric lens5.

The circuit boards4disposed on sides of the high-frequency wave circuits1and2are arranged on the back of the dielectric lens5. That is, the circuit boards4are arranged inside the aperture diameter of the dielectric lens5. These circuit boards4and the other circuit board3are connected to each other with flexible substrates7therebetween.

The high-frequency wave circuit1preferably includes a power amplifier and an oscillator, and in order to transmit the heat produced by these units to the case11, an elastic heat-transmission member12is interleaved between the high-frequency wave circuit1and the case11. The case11is preferably formed by die casting of aluminum, and is excellent in heat dissipation because the thermal conductivity and the radiation area are large.

As shown inFIG. 1, on the open surface of the case11, a flange is formed, which has screw insertion holes hs formed at four corners of the flange. As shown inFIG. 2, the case11is fixed to the mounting member10by screwing into thread holes h of the mounting member10from the side of the case11in a state that the open surface of the case11is abutted to the mounting member10.

On the front surface of the mounting member10, the dielectric lens5is arranged so as to cover the open surface of the mounting member10, and by fitting the lens cover6to the mounting member10, the mounting member10, the dielectric lens5, and the lens cover6are integrated.

In order to attach the radar head module described above to the frame20, screw holes formed in the supporting portions10aof the mounting member10and screw holes formed in the frame20are fixed to each other by screwing with bolts with washers14therebetween.

In order to adjust characteristics of the radar head module described above, the radar head module is fixed to a predetermined jig without having the case11attached thereto, and by measuring the characteristics, the high-frequency wave circuits1and2or the circuit boards3and4are adjusted so as to obtain predetermined characteristics. Then, the case11may be attached thereto.

If this radar head module is adjusted in characteristics in a state attached to a body upon which the radar is to be mounted, such as a vehicle, in which the module is finally used, without the cover11attached thereto, and then the cover11is attached thereto, the adjustment for obtaining predetermined characteristics under circumstances, in which the module is practically used, can be readily performed.

FIG. 3is a block diagram of a structure of the radar head module described above. Wherein symbol VCO denotes a voltage-controlled oscillator using a Gunn diode and a varactor diode, symbol PA denotes a power amplifier for power-amplifying an originating signal. An isolator ISO prevents a reflected signal from returning to the power amplifier PA. A coupler CPL is a directional coupler including an NRD guide for deriving a portion of a transmitting signal as a local signal. A circulator CIR gives a transmitting signal to a scan unit while transmitting a receiving signal toward a mixer MIX. The mixer MIX mixes the receiving signal with the local signal mentioned above so as to output an intermediate-frequency signal IF.

From the modulated signal and IF signal mentioned above, the relative distance and relative speed of a target are detected by an FM-CW system.