Graphene/AlGaN/GaN RF Switch

RF switches, which use a combination of graphene and two-dimensional high-density electron gas (2DEG) in the AlGaN/GaN system, were proposed and studied in the frequency band from 10 MHz to 114.5 GHz. The switches were integrated into the coplanar waveguide, which allows them to be used in any system without the use of, e.g., bonding, flip-chip and other technologies and avoiding the matching problems. The on-state insertion losses for the designed switches were measured to range from 7.4 to 19.4 dB, depending on the frequency and switch design. Although, at frequencies above 70 GHz, the switches were less effective, the switching effect was still evident with an approximately 4 dB on–off ratio. The best switches exhibited rise and fall switching times of ~25 ns and ~17 ns, respectively. The use of such a switch can provide up to 20 MHz of bandwidth in time-modulated systems, which is an outstanding result for such systems. The proposed equivalent circuit describes well the switching characteristics and can be used to design switches with required parameters.

A Pine Shaped Dual-Band Frequency Reconfigurable Antenna

In recent years reconfigurable antennas have attracted a lot of attention in modern wireless communication systems. In satellite communication and ECM system, there has always been a continuous demand for smaller size, lighter weight antenna system that has properties to accomplish selectivity in frequency, bandwidth, polarization and gain. A frequency reconfigurable antenna is proposed for wireless communication. We can achieve Frequency reconfiguration by modifying physical or electrical dimensions of the antenna using RF-switches, impedance loading or tunable material. The design and simulation of the proposed antennas are done using ANSYS high-frequency structure simulator (HFSS) version-19. The proposed antenna is taken as a triangular shape whose length and width are 50mm and 25mm respectively. Here reconfigurability is achieved by RF switches placed in the radiator. The antenna analysis is done by taking different conditions of the switch. Total four switching condition is simulated and for each case, distinctive resonating frequencies are accomplished with acceptable reflection coefficient. The frequency bands of the antenna are varied from 2.12 GHz to 5.27 GHz. This antenna covers S-band and C band. After simulating the design the gain and efficiency of the antenna are verified successfully. Antenna fabrication and measurement of different parameters will be done in future. A comparison of the measured result will be analyzed with some existing antenna outcomes.