| 摘要 |
PROBLEM TO BE SOLVED: To provide an antenna which can cope with plural frequency bands by switching the grounded and non-grounded states of a control electrode that is placed near the open end of a radiation electrode via a gap and accordingly switching the resonance frequency of the antenna. SOLUTION: A ground electrode 3 is formed on the entire surface of on one of both main sides of a rectangular parallelepiped-shape dielectric substrate 2 together with a radiation electrode 4 formed on the other main side of the substrate 2 respectively, and one of both ends of the electrode 4 is grounded. In such a constitution, a surface mounting antenna 1 is produced. The signal inputted to a feeding electrode 6 from a signal source 10 is inputted to the electrode 4 via a 1st gap 5 formed near the open end of the electrode 4. Thus, the electrode 4 resonances as a microstrip line resonator whose one of both ends is opened with the other end having its short circuit length of λ/4. A control electrode 8 is placed near the open end of the electrode 4 via a 2nd gap 7, and the grounded and non-grounded states of the electrode 8 are controlled by a switch 9. When the switch 9 is turned on, the capacities generated between the electrode 4 and the electrode 8 are applied in parallel to each other to lower the resonance frequency. |
