Differential-feed slot antenna

A differentially-fed variable slot antenna comprising:

• a dielectric substrate;
• a ground conductor surface provided on a rear face of the dielectric substrate;
• a differential feed line disposed on a front face of the dielectric substrate, the differential feed line being composed of two mirror symmetrical signal conductors;
• a first slot resonator formed on the ground conductor surface;
• and
• a second slot resonator formed on the ground conductor surface, wherein,
• a portion of the first slot resonator intersects one of the two mirror symmetrical signal conductors but does not intersect the other signal conductor;
• a portion of the second slot resonator does not intersect the one signal conductor among the two mirror symmetrical signal conductors but intersects the other signal conductor;
• a slot length of the first slot resonator corresponds to a ½ effective wavelength at an operating frequency;
• a slot length of the second slot resonator corresponds to the ½ effective wavelength at the operating frequency;
• the two mirror symmetrical signal conductors are fed out-of-phase;
• at least one of the first slot resonator and the second slot resonator has at least one function wherein the at least one function comprises an RF structure reconfigurability function or an operation status switching function, thus realizing a radiation characteristics reconfigurable effect resulting into at least two states;
• the first and second slot resonators each comprise a series connection structure in which a feeding portion partly intersecting the signal conductor is connected in series to a selective radiation portion not intersecting the signal conductor;
• in the at least one of the first and second slot resonators having the at least one function, a high-frequency switching element inserted between the feeding portion and the selective radiation portion provides control as to whether or not to connect between regions of the ground conductor surface which are on both sides astride the slot resonator;
• in the at least one of the first and second slot resonators having the RF structure reconfigurability function, a plurality of said selective radiation portions are connected to the feeding portion each in series connection, and the high-frequency switching elements are controlled so that only one selective radiation portion among the plurality of selective radiation portions is connected to the feeding portion in an operating state;
• and
• in the at least one of the first and second slot resonators having the operation status switching function, the high-frequency switching element is controlled so that connection between the feeding portion and the selective radiation portion is terminated in a non-operating state.