Abstract: A wireless communication device for transmitting and receiving radio waves of a target frequency includes a ground plate having a rectangular shape, a zeroth-order resonant antenna element arranged at a position shifted from a center of the ground plate in a lengthwise direction of the ground plate, and a circuit module configured to transmit and receive signal via the zeroth-order resonant antenna element. The zeroth-order resonant antenna element includes a counter conductor plate arranged at a predetermined distance from the ground plate and having a feed point connected to a feedline, and a short circuit portion electrically connecting the counter conductor plate and the ground plate. The ground plate, the counter conductor plate and the short circuit portion are configured to cause parallel resonance at the target frequency and satisfy a condition that resonance caused by the ground plate is reduced.

Abstract: An in-vehicle system executes authentication of a mobile device multiple times from a parking state until an engine is started. The in-vehicle system operates in an alert mode when a vehicle is parked, and transmits an authentication signal including a strength change signal. When the in-vehicle system operates in an alert cancellation mode, the mobile device returns a response signal only when there is a change in the strength of the received authentication signal. When the in-vehicle system succeeds in authentication of the mobile device in an authentication process in the alert mode, the in-vehicle system shifts to the alert cancellation mode. When the in-vehicle system operates in the alert cancellation mode, the mobile device returns the response signal irrespective of whether there is the change in the strength of the received authentication signal.

Abstract: An in-vehicle system executes authentication of a mobile device multiple times from a parking state until an engine is started. The in-vehicle system operates in an alert mode when a vehicle is parked, and transmits an authentication signal including a strength change signal. When the in-vehicle system operates in an alert cancellation mode, the mobile device returns a response signal only when there is a change in the strength of the received authentication signal. When the in-vehicle system succeeds in authentication of the mobile device in an authentication process in the alert mode, the in-vehicle system shifts to the alert cancellation mode. When the in-vehicle system operates in the alert cancellation mode, the mobile device returns the response signal irrespective of whether there is the change in the strength of the received authentication signal.

Abstract: In a wireless communication system, a portable device and an in-vehicle device wirelessly communicate with each other by a spread spectrum method. The in-vehicle device transmits a synchronization signal indicative of a reference period to the portable device. The in-vehicle device performs code acquisition for only a portion of a spread wireless signal received from the portable device. The portion has a starting point in a search period from a search start point to a search end point. The search start point is identified based on the reference period and a predetermined first correction time. The search end point is identified based on the reference period and a predetermined second correction time.

Abstract: A radio signal detector includes first and second detector circuits. The first detector circuit has a higher detection sensitivity to detect a radio signal earlier than the second detector circuit. The second detector circuit has a lower detection sensitivity to detect the radio signal accurately. When the second detector circuit detects the radio signal, it starts up a microcomputer. When the first detector circuit detects the radio signal, a time counter starts to count time. After being started up, the microcomputer acquires a time difference between the radio signal detection by the first detector circuit and the start-up. The microcomputer determines time of radio signal transmission by a radio signal transmitter device based on the determined time difference, and outputs control information after an elapse of a predetermined time.

Abstract: A radio signal detector includes first and second detector circuits. The first detector circuit has a higher detection sensitivity to detect a radio signal earlier than the second detector circuit. The second detector circuit has a lower detection sensitivity to detect the radio signal accurately. When the second detector circuit detects the radio signal, it starts up a microcomputer. When the first detector circuit detects the radio signal, a time counter starts to count time. After being started up, the microcomputer acquires a time difference between the radio signal detection by the first detector circuit and the start-up. The microcomputer determines time of radio signal transmission by a radio signal transmitter device based on the determined time difference, and outputs control information after an elapse of a predetermined time.

Abstract: In a wireless communication system, a portable device and an in-vehicle device wirelessly communicate with each other by a spread spectrum method. The in-vehicle device transmits a synchronization signal indicative of a reference period to the portable device. The in-vehicle device performs code acquisition for only a portion of a spread wireless signal received from the portable device. The portion has a starting point in a search period from a search start point to a search end point. The search start point is identified based on the reference period and a predetermined first correction time. The search end point is identified based on the reference period and a predetermined second correction time.

Abstract: An antenna coil includes: an air-core type flat coil body; and a coil support member disposed between the coil body and a substrate so that the coil body is supported on a surface of the substrate. The thickness of the coil body is smaller than a radius of a circle, an area of which is equal to an area of a region surrounded with an outline of a projected coil body, the projected coil body provided by projecting the coil body on a projection plane perpendicular to the axial direction of the coil body. The coil support member is made of resin hardened soft magnetic material.

Abstract: A portable device in an electronic key system has a motion detection sensor to detect its motion from a continuation of standing state over a specified period of time, sound and vibration are generated. This sound and vibration make the user aware that he or she carries the portable device. The user thus is reminded of carrying the portable device whenever he or she goes out. If the motion detection sensor detects a larger motion, the sound and vibration are generated without checking the specified period of time. The motion may also be reported to handy equipment, which is separate from the portable device and carried by the user.

Abstract: An in-vehicle LF transmitter transmits a synchronization signal to an in-vehicle RF receiver and transmits LF data (response request) including a synchronization signal to a portable device. The portable device performs RF data output and DSSS process and transmits RF data (response) subjected to spread process. The in-vehicle RF receiver receives the RF data and performs despread process. Both of the spread process of the portable device and the despread process of the in-vehicle RF receiver are performed by the use of a spread code the period of which is adjusted based on the synchronization signal transmitted from the in-vehicle LF transmitter.

Abstract: A communication module is mounted in a user-carried portable telephone, so that the portable telephone and the communication module cooperate. When a user performs a vehicle wheel physical state request operation, a wheel physical state request signal is transmitted to a wheel physical state transmitter, so that wheel physical state data is received from the wheel physical state transmitter and displayed on a display device. Further, on receiving a probe signal from a smart entry vehicle unit, a lock/unlock signal is transmitted for automatically unlocking doors of the vehicle. When a user performs a lock/unlock operation, an unlock signal is transmitted for locking or unlocking doors of the vehicle.

Abstract: A portable device search system for an electronic key system is formed by a portable device and handy equipment such as a cellular phone, PDA and the like, which is separate from the portable device. When a predetermined operation is performed on the handy equipment, the handy equipment transmits a search signal. On receiving the search signal, the portable device generates a specific sound and vibration to notify the location. In addition, an image near the portable device may be transmitted to the handy equipment to be displayed on the handy equipment.

Abstract: An antenna coil includes: an air-core type flat coil body; a coil case; and a reinforce frame. The coil case has a ring shape, which corresponds to the coil body. The coil case includes a coil accommodation space. The coil case further includes a coil side terminal. The reinforce frame is integrated with the coil case along with the circumferential direction of the ring shape of the coil case. The reinforce frame is made of a material having a Young' modulus higher than that of the resin of the coil case.

Abstract: An antenna coil includes: an air-core type flat coil body having a ring shape; and a coil case having a ring shape corresponding to the ring shape of the coil body. The coil case includes a coil accommodation space for accommodating the coil body. The coil accommodation space is disposed in a circumferential direction of the ring shape of the coil case. The coil body includes a plurality of unit coils, each of which has a same winding direction and a same number of turns. The unit coils are connected in parallel each other.

Abstract: An antenna coil includes: an air-core type flat coil body; and a coil support member disposed between the coil body and a substrate so that the coil body is supported on a surface of the substrate. The thickness of the coil body is smaller than a radius of a circle, an area of which is equal to an area of a region surrounded with an outline of a projected coil body, the projected coil body provided by projecting the coil body on a projection plane perpendicular to the axial direction of the coil body. The coil support member is made of resin hardened soft magnetic material.

Abstract: An antenna coil includes: an air-core type flat coil body; a coil case; and a reinforce frame. The coil case has a ring shape, which corresponds to the coil body. The coil case includes a coil accommodation space. The coil case further includes a coil side terminal. The reinforce frame is integrated with the coil case along with the circumferential direction of the ring shape of the coil case. The reinforce frame is made of a material having a Young' modulus higher than that of the resin of the coil case.

Abstract: A wireless communicating apparatus includes a circuit board; a circuit component attached to the circuit board; a terminal provided to the circuit board for electrically linking the circuit component with an external apparatus for the circuit component and the external apparatus to communicate a signal; and a casing made of a resin-sealing material for directly covering a surface of the circuit component and a surface of the circuit board to which the circuit component is attached, while the casing includes a through-hole through which the terminal is exposed to an outside.

Abstract: A communication module is mounted in a user-carried portable telephone, so that the portable telephone and the communication module cooperate. When a user performs a vehicle wheel physical state request operation, a wheel physical state request signal is transmitted to a wheel physical state transmitter, so that wheel physical state data is received from the wheel physical state transmitter and displayed on a display device. Further, on receiving a probe signal from a smart entry vehicle unit, a lock/unlock signal is transmitted for automatically unlocking doors of the vehicle. When a user performs a lock/unlock operation, an unlock signal is transmitted for locking or unlocking doors of the vehicle.

Abstract: A portable device in an electronic key system has a motion detection sensor to detect its motion from a continuation of standing state over a specified period of time, sound and vibration are generated. This sound and vibration make the user aware that he or she carries the portable device. The user thus is reminded of carrying the portable device whenever he or she goes out. If the motion detection sensor detects a larger motion, the sound and vibration are generated without checking the specified period of time. The motion may also be reported to handy equipment, which is separate from the portable device and carried by the user.

Abstract: A portable device search system for an electronic key system is formed by a portable device and handy equipment such as a cellular phone, PDA and the like, which is separate from the portable device. When a predetermined operation is performed on the handy equipment, the handy equipment transmits a search signal. On receiving the search signal, the portable device generates a specific sound and vibration to notify the location. In addition, an image near the portable device may be transmitted to the handy equipment to be displayed on the handy equipment.