▎ 摘　　要

NOVELTY - The filter has a medium substrate (1) whose two sides are symmetrically provided with a micro-strip feeder line structure (2). The micro-stripe feeder is provided with the micro-strip resonant structure (3). A side of the micro-stripe resonant is connected with a side of a graphene nano-plate (7). A metal sheet (8). A lower surface of the medium substrate is formed with a metal floor (6). USE - Balance filter with adjustable attenuation for use as frequency selection device in wireless communication system. Can also be used as double-port filter and double-line transmission structure. ADVANTAGE - The balance filter is capable of adjusting attenuation, realizing attenuation adjustable function of balance filter, at the same time, reducing the device size on the basis of not affecting the performance, improving the integration degree of the device, simple structure, economical efficiency and strong practicability. The adjustable attenuation function is realized by the cascade of the balance filter and the adjustable attenuator, the use of graphene nano-in the microwave frequency band is mainly represented characteristics the resistance of the resistor, and the surface impedance can characteristics along with the external voltage, the conductivity is adjustable and the volume is adjustable. The graphene nanometre plate is equivalent to a variable resistor in series with the micro-strip resonant structure, causing the resonator input impedance real part to be not zero, when changing the bias voltage on the graphene nano plate. DESCRIPTION OF DRAWING(S) - The drawing shows an integral structure schematic diagram of a balance filter of adjustable attenuation. 1Medium substrate 2Micro-strip feeder structure 3Micro-strip resonant structure 6Metal floor 7Graphene nano plate 8Metal sheet