Mobile antenna unit and accompanying communication apparatus

1. An antenna unit, comprising:

an inverted F-type antenna element provided with a feeding point and a ground connection point; and

a non-feed antenna element configured to resonate with said inverted F-type antenna element by electrical coupling,

wherein a surface of said non-feed antenna element facing said inverted F-type antenna element is trapezoid-shaped, and a base of said trapezoid shape is along a direction of resonance with said inverted F-type antenna element.

2. The antenna unit according to claim 1 , wherein said inverted F-type antenna element and said non-feed antenna element have electrical coupling planes which are generally parallel, one with the other.

3. The antenna unit according to claim 1 , wherein said non-feed antenna element has two or more different lengths along a direction of resonance with said inverted F-type antenna element.

4. The antenna unit according to claim 1 , wherein said non-feed antenna element comprises two or more non-feed antenna elements, the lengths of which are different along a direction of resonance with said inverted F-type antenna element.

5. The antenna unit according to claim 4 , wherein each of said two or more non-feed antenna elements has two or more different lengths along a direction of resonance with said inverted F-type antenna element, and wherein a shortest side of each non-feed antenna element faces a shortest side of another non-feed antenna element along a direction of resonance with said inverted F-type antenna element.

6. The antenna unit according to claim 1 , wherein: said non-feed antenna element comprises a first non-feed antenna element and a second non-feed antenna element, each of which element is trapezoid shaped having a top side and a base aligned along a direction of resonance with said inverted F-type antenna; and wherein said top sides, being shorter than said bases, face each other.

7. The antenna unit according to claim 1 , further comprising: a U-shaped shield part grounded to the earth and surrounding a back side of said antenna unit, said back side being in a direction of radiation of electromagnetic waves by said antenna unit, and further surrounding the sides of said inverted F-type antenna element and said non-feed antenna element in the same plane as said inverted F-type antenna element.

8. The antenna unit according to claim 1 , further comprising: an insulating substrate comprising top and bottom surfaces, wherein said inverted F-type antenna element is provided on the top surface and said non-feed antenna element is provided on the bottom surface of said substrate.

9. The antenna unit according to claim 1 , further comprising: a ground part grounded to the earth, which is connected to said ground connection point provided on one edge of said inverted F-type antenna element; and a resonance element, one edge of which is connected to said ground part, and which is configured to be resonated by said non-feed antenna element through electrical coupling.

10. The antenna unit according to claim 9 , wherein said resonance element extends in a direction that maintains a distance between said inverted F-type antenna element and said edge of said resonance element that is connected to said ground part.

11. The antenna unit according to claim 9 , wherein when a first frequency signal is supplied to said feeding point, said inverted F-type antenna element oscillates and said non-feed antenna element resonates, so that said antenna unit radiates an electric wave corresponding to said first frequency signal as a waveguide device, and when a second frequency signal lower than said first frequency is supplied to said feeding point, said inverted F-type antenna element, said non-feed antenna element and the resonance element oscillate in the shape of a loop, so that said antenna unit radiates an electric wave corresponding to said second frequency signal.