Abstract: A transmission line portion of a flat cable that is bent at a position along the longitudinal direction includes a dielectric element body, a first ground conductor, and a second ground conductor. The dielectric element body includes a signal conductor at the middle position of the thickness direction. The first ground conductor includes elongated conductors and bridge conductors. The elongated conductors are spaced in the width direction of the dielectric element body, and extend in the longitudinal direction. The bridge conductors connect the elongated conductors at spacings along the longitudinal direction. The spacing of bridge conductors across the bending point in a bent portion is smaller than the spacing of adjacent bridge conductors located in a straight portion.

Abstract: A transmission line portion of a flat cable that is bent at a position along the longitudinal direction includes a dielectric element body, a first ground conductor, and a second ground conductor. The dielectric element body includes a signal conductor at the middle position of the thickness direction. The first ground conductor includes elongated conductors and bridge conductors. The elongated conductors are spaced in the width direction of the dielectric element body, and extend in the longitudinal direction. The bridge conductors connect the elongated conductors at spacings along the longitudinal direction. The spacing of bridge conductors across the bending point in a bent portion is smaller than the spacing of adjacent bridge conductors located in a straight portion.

Abstract: This disclosure provides an antenna apparatus in which stable antenna characteristics are maintained by detecting surrounding conditions that affect the antenna characteristics and appropriately compensating the antenna characteristics. More specifically, when surrounding condition such as a human body (e.g., a palm or fingers) approaches and enters an electric field of a pseudo dipole formed by an antenna element electrode, a stray capacitance is sensed and stable antenna characteristics are maintained by appropriately controlling an antenna matching circuit to compensate for a change in the antenna characteristics due to the approach of the surrounding condition.

Abstract: A switching function and multiband compatibility and a function handling deviation of matching caused by the influence of the human body are configured in a single matching circuit. An antenna matching circuit is formed by a reactance changing section and a matching section. The matching section is formed by a parallel circuit of an inductor and a capacitor, and the LC parallel circuit is shunt-connected between a feed section and the ground. The reactance changing section changes the resonant frequency to be compatible with a plurality of bands, and performs fine adjustment of the resonant frequency changed by the influence of the human body. The parallel inductor causes the locus of input impedance of the antenna matching circuit to draw a small circle locus in the first quadrant of a Smith chart. The parallel capacitor is adjustable to move the small circle locus to the center on the Smith chart.

Abstract: This disclosure provides an antenna coil for a circuit board including a ground conductor serving as a planar conductor, a feed circuit for connecting to the antenna coil and various electronic components constituting a mobile communication terminal that are mounted on the front and/or back surfaces of the circuit board. The antenna coil includes a magnetic core having a first principal surface and a second principal surface, and a coil conductor wound around the magnetic core. The coil conductor has a first conductor portion located adjacent to the first principal surface of the magnetic core, and a second conductor portion located adjacent to the second principal surface of the magnetic core and at a position different from that of the first conductor portion in plan as viewed from the first principal surface or the second principal surface.