Antenna for communication terminal apparatus
The unbalanced feeding antenna element 201 is fed power from one end and placed on the upper surface of the circuit substrate 103 . The passive element 202 has open both ends, is set to a length corresponding to a predetermined frequency, placed in substantially parallel to the unbalanced feeding element 201 placed on the circuit substrate 103 at a distance of approximately 1/10 or less of a wavelength at a frequency used for transmission/reception. This suppresses the antenna current flowing into the circuit substrate 103 to a minimum level and makes radiation from the passive element 202 dominant compared to radiation from the circuit substrate 103 . This makes it possible to suppress a reduction in the antenna gain caused by the human body when the user uses the communication terminal apparatus.
1. An antenna for a communication terminal apparatus, the antenna comprising:
a first feeding element and a second feeding element, wherein an end of the first or second feeding element is fed with power in an unbalanced manner;
a first passive element placed substantially in parallel to said first feeding element at a distance of approximately 1/10 or less of the wavelength at a frequency used for transmission/reception, the first passive element having a length of resonance when said first feeding element is excited; and
a second passive element placed substantially in parallel to said second feeding element at a distance of approximately 1/10 or less of the wavelength at the frequency used for said transmission/reception, the second passive element having a length of resonance when said second feeding element is excited, wherein:
said first feeding element, said second feeding element, said first passive element, and said second passive element are placed at positions distant from the position at which a user of the communication terminal apparatus holds said communication terminal apparatus.
2. The antenna for a communication terminal apparatus according to claim 1 , further comprising:
a third passive element differing in length from said first passive element, the first passive element having the same length as that of said second passive element, and a fourth passive element having the same length as that of said third passive element, wherein:
said third passive element is placed substantially in parallel to said first feeding element at a distance of approximately 1/10 or less of the wavelength of a frequency different from the frequency used for transmission/reception by said first passive element and said second passive element, and
said fourth passive element is placed in substantially parallel to said second feeding element at a distance of approximately 1/10 or less of the wavelength of the frequency different from the frequency used for transmission/reception by said first passive element and said second passive element.
3. The antenna for a communication terminal apparatus according to claim 1 , wherein said first feeding element and said second feeding element are placed in such a way that the angle formed by the orientation of said first feeding element and the orientation of said second feeding element is substantially a right angle.