Antenna, and wireless module, wireless unit and wireless apparatus having the antenna

An antenna comprising:

• first and second transmission lines;
• a variable capacitance diode;
• a feed point;
• a resistor;
• and
• a control signal input terminal,
• wherein said variable capacitance diode having its one end electrically grounded and its other end connected through said resistor to said control signal input terminal and also connected through said first transmission line to said feed point, the feeder-end side end of said first transmission line being electrically grounded through said second transmission line, a DC reverse voltage supplied from said control signal input terminal being used to control the capacitance value of said variable capacitance diode which controls the resonant frequency.