A 1-Bit Coding Reconfigurable Metasurface Reflector for Millimeter Wave Communications in E-Band

In this paper, a millimeter wave (mmWave) 1bit coding metasurface is presented. The unit cell of the metasurface consists of a modified dipole loaded with a Macom MA4AGFCP910 PIN diode, which works quite satisfactorily at E-band mmWave. The unit cell provides a $180^{\circ} \pm 30^{\circ}$ reflection phase difference between its ON and OFF states for a broad frequency range from $74-84 \mathrm{GHz}$ (12.65 %). Despite being a PCB-based design at E-band, the unit cell provides maximum reflection loss of only 2.7dB. Using such unit cell, an array of $30 \times 15$ elements is constructed with column-by-column arrangement of biasing for the PIN diodes to achieve 1-D beam steering. Furthermore, the RF is isolated from the DC on the bias lines using properly designed radial stubs. The theoretically calculated and full-wave simulated results of radiation patterns show good agreement with each other. The effect of beam squint and scan loss from the proposed broadband 1-bit coding metasurface is critically investigated. The design can find application in different mmWave communications in E-band.