Photonic antenna operating in 275-296 gigahertz

A photonic antenna operating in 275-296 gigahertz (GHz), comprising:

• uni-traveling-carrier photodetectors (UTC-PDs);
• and
• a passive structure, comprising impedance matching circuits, a power-combiner, and a Vivaldi antenna;
• wherein the UTC-PDs are two in quantity, each UTC-PD adopts a double-mesa structure, the two identical UTC-PDs each have electrodes routed via electroplated micro-pads, with each electroplated micro-pad processed with metallic bumps, and the UTC-PDs are electrically connected to the passive structure fabricated on a quartz substrate by flip-chip bonding;
• wherein the two UTC-PDs respectively correspond to the impedance matching circuits;
• the impedance matching circuits are two in quantity and arranged symmetrically;
• the impedance matching circuits are fabricated on the quartz substrate with a relative dielectric constant of 3.78;
• each impedance matching circuit comprises a serial transmission line, a short-circuited stub line, and a metal-insulator-metal (MIM) capacitor;
• and both the serial transmission line and the short-circuited stub line are implemented in coplanar waveguide configuration;
• wherein the power-combiner is a T-junction power combiner used after the impedance matching circuits to superimpose two impedance-matched signals, where a first terminal and a second terminal of the power combiner respectively correspond to output terminals of the two impedance matching circuits;
• wherein the T-junction power combiner comprises:
• the first terminal and the second terminal, a quarter-wavelength impedance transforming part, and a third terminal;
• and the Vivaldi antenna is connected to the third terminal of the T-junction power combiner, and the Vivaldi antenna is fed by a coplanar waveguide:
• wherein the Vivaldi antenna comprises a feeding terminal, a radiating structure, and a reflecting structure;
• wherein the feeding terminal adopts a coplanar waveguide structure that is identical to a structure of the third terminal of the T-junction power combiner;
• and
• wherein the radiating structure comprises an exponentially changing open structure, radiating sheets of the Vivaldi antenna are defined with slots to enhance gain, and metal blocks are disposed at a middle position of the quartz substrate to direct;
• and the reflecting structure in an arc shape is formed on a rear surface of the quartz substrate to reduce a rear lobe gain and a side lobe gain.