Abstract: In a digital mobile radio apparatus according to the present invention, a duplexer for connecting a transmitter and a receiver to a common receiving/transmitting antenna is constructed from an isolator and a receiving band-pass filter. The receiving band-pass filter prevents a transmitted wave from entering the receiver. Impedance matching is effected so that the isolator can prevent a received wave from entering the transmitter while suppressing the entrance of signals radiated from other mobile units in the same transmitting frequency band but at a different operating frequency.

Abstract: A direct connect antenna includes a passive patch-type antenna mounted to a radio, wherein the need for and use of a coaxial cable extension arrangement is eliminated. Thus, the characteristic impedances of the load and source can be better matched, resulting in lower reflection and distributed losses. The antenna is formed with guide slots for alignment and simple snap-on connection of the antenna to the radio to prevent coaxial connector mismatch and damage. The radio may be directly affixed and electrically coupled to a PCMCIA compliant interface card which is insertable into a host computer. Accordingly, radio signals received by the direct connect antenna and radio arrangement are processed through the PC card and the computer.

Abstract: A mobile communication terminal or telephone comprising a handheld main housing incorporating a digital keypad, a speaker and a microphone, and having a planar radiator antenna. The antenna is hingedly-attached to an extension arm element which, in turn, is hingedly-attached at the top of the main housing. During use, the antenna is pivoted above and away from the head of the user by a sufficient distance to significantly reduce or remove the exposure of the user to transmitted RF power of sufficient density to pose a health danger.

Abstract: A wearable audio reception device includes an elongated flexible enclosure removably attachable to an article of clothing and the radio in turn being removably attachable to the flexible enclosure.

Abstract: A computer card data receiver (10) includes a housing (14) having a top planar surface (16) and a bottom planar surface (18) and a thin profile suited to fit within a recessed data interface port (32) of an external computer (30). An antenna (12) is coupled to the top planar surface (16) of the housing (14) for intercepting transmitted selective call address signals and data associated therewith. The antenna (12) is rotatable between a first antenna position (12A) and a second antenna position (12B), the first antenna position (12A) being selected when the housing (14) is removed from the recessed data interface port (32), and the second antenna position (12B) being selected when the housing (14) is inserted into the recessed data interface port (32). A receiver (40) is enclosed within the housing (14) and receives and detects the intercepted selective call address signals and data associated therewith.

Abstract: A polarization diversity radio communication system suitable for radio communication in indoor space is provided for transmitting from a transmitter a series of data sequentially from one of two or more transmission antennas of the transmitter, and for reproducing the data received at a receiver through a single reception antenna of the receiver when the series data are received from the transmitter. Thus, the transmitted data from any part of the indoor space can be received efficiently, and a high S/N ratio can be assured on the reception side.

Abstract: A loop antenna (10) for use in a wrist band radio (50) comprises a series of interconnected links (2 and 4) forming a wristband, a flexible conductor (30) retained between the interconnected links forming the loop antenna, and a connector at the end portions of the series of links for electronically coupling the flexible conductor to the radio.

Abstract: A telephone apparatus for a vehicle comprising a main antenna and a sub-antenna. The sub-antenna is operated to receive incoming electric waves including an incoming call signal. When the sub-antenna receives the incoming call signal or when an outgoing call signal is outputted, the main antenna is extended and an transmitter-receiver of the telephone apparatus is turned on. When the conversation by the telephone apparatus is finished, the main antenna in an extended condition is contracted and received in the vehicle, and the transmitter-receiver is turned off.

Abstract: A small antenna for portable radios and the like in which two planar conductive boards are disposed in parallel relationship at a spaced interval which is small when compared with received radio wavelengths. A dielectric frame is disposed between the two planar conductive boards keeping them at the preselected spaced interval. Arbitrary feeding points are selected along the edges of the two conductive boards and at least one conductor is positioned at an arbitrary selected feeding point to short-circuit the two conductive boards. In some cases a plurality of arbitrary feeding points may be selected along the edges of the two conductive boards and a plurality of conductors positioned at the plurality of arbitary selected feeding points which short-circuits the conductive boards. The positions of the plurality of conductors which short-circuit the conductive boards may be automatically changed at will to provide the most desirable condition responsive to the direction of the radio waves.

Abstract: A portable radio receiver assembled in a case. In accordance with the present invention, the case is also employed as an antenna of the portable receiver. The case is composed of a pair of parallel-opposed square conductor plates interposed therebetween a space sufficiently smaller than the wavelengths of received waves of the portable radio receiver, a frame of insulating material interposed in the space. Feeding terminals of the portable radio receiver are provided at desired positions on one pair of opposed sides of the parallel-opposed square conductor plates. Each of short-circuit elements of high-frequency-wise is provided on other pair of opposed sides of the parallel-opposed square conductor plates so that the direction of the plane of polarization of the antenna can be changed by short-circuiting any one of the short-circuit elements.

Abstract: Disclosed is here an apparatus for automatically adjusting a length of the antenna of the radio receiver in which the antenna is disposed to be integral with a high-frequency circuit section and a tuning circuit is configured to be in a variable capacity system. The apparatus includes a unit for detecting a condition that an intensity of an antenna input electric field is at least an optimal range so as to generate a first signal, a unit for detecting a condition that the intensity of the antenna input electric field is at most an optimal range so as to generate a second signal, a unit for detecting a condition that an interference signal is at least at a predetermined level so as to generate the second signal, a device for elongating the antenna based on the first signal, and a device for shortening the antenna based on the second signal.

Abstract: An antenna has a main vertical planar part which is connected at its one end to the ground, and a main horizontal planar part which are both arranged in an L-shape. It has a secondary vertical linear part which is arranged in parallel with the main vertical planar part and connected at its one end to the feeding point. It also has a conductive secondary horizontal linear part which is connected between the main horizontal planar part and the secondary vertical linear part and is arranged in parallel with the main horizontal planar part, while being separated from the main horizontal planar part by a definite distance. This makes it possible to incorporate the antenna in the circuit board of wireless communication equipment, and the antenna is particularly suitable for miniaturizing the equipment.

Abstract: A fixed length antenna rod projects from a housing enclosing a pre-amplifier circuit connecting it to the front end of a FM receiver. The antenna rod is mounted at an optimum signal reception attitude by the flange of a bracket to which the housing is secured and through which an output cable terminal of the pre-amplifier circuit extends. The preamplifier circuit is adjustably tuned to favor a specific frequency for subcarrier transmission and attenuated in signal gain to match antenna signal pick-up level.

Abstract: A compact police radar warning receiver is provided having an antenna in which all of the mixer and oscillator components are mounted to one side of the antenna enabling the exterior wall of the side opposite thereto to be constructed substantially flat and thereby function as one of the exterior walls of the housing. The antenna is further provided with an improved microwave oscillator, an impedance transformer and non-adjustably positioned tuning pins.

Abstract: The antenna for equipping a portable receiver comprises a metal plate and a metal box containing the receiver components and which is provided with a surface facing the metal plate, the metal box behaving in the manner of a virtual plate positioned half-way up the box.

Abstract: A miniature handheld receiver contained in a metal shielding enclosure incorporating a slot type directional antenna as a part of the structure such that when the antenna is aligned with a radio frequency signal of interest, a null is produced in the signal level. The antenna is coupled to receiver circuitry which includes an oscillator used to FM modulate the signal by tone injection when an unmodulated carrier is present, an FM detector for demodulating the RF signal, an audio amplifier for amplifying the demodulated audio and an acoustically coupled earphone to prevent stray RF pickup from the earphone cord.

Abstract: An integrated antenna-detector device sensitive over a broadband of frequencies with an extended high frequency limit comprising a pair of antenna elements each having first and second ends, the first ends of the elements being positioned proximate to each other while the second ends are displaced from the first ends, a detector unit positioned and connected between the first ends of the antenna elements, and signal output means connected with the antenna elements at a location displaced from their first ends. The signal output means delivers detected output signals from the antenna elements, and also delivers a biasing signal to the detecting unit. The device may take a number of forms including that of a dipole antenna having a linear or conical configuration, and in which a plurality of such dipole elements are arranged to form a log-periodic antenna, and where the pair of antenna elements are arranged to provide a pair of interwound spiral conductive windings to form a spiral antenna.