No abstract

Measurement of the dielectric properties of ocular tissues up to 110 GHz was performed by the coaxial probe method. A coaxial sensor was fabricated to allow the measurement of small amounts of biological tissues. Four-standard calibration was applied in the dielectric property measurement to obtain more accurate data than that obtained with conventional three-standard calibration, especially at high frequencies. Novel data of the dielectric properties of several ocular tissues are presented and compared with data from the de facto database.

We fabricated an optically transparent dipole antenna based on chemical vapor deposition (CVD)-grown monolayer graphene on an optically transparent quartz substrate and characterized its properties in microwave bands. The measurements of the reflection coefficients for the dipole antenna revealed that ∼90% of the microwave power transmitted to the CVD monolayer graphene of the antenna element. By measuring transmission coefficients, we demonstrated that the graphene dipole antenna radiated microwave power around the operational frequency (∼20.7 GHz). The operational frequency of the graphene dipole antenna (∼20.7 GHz) shifted to a higher frequency than that of the Au dipole antenna with the same structure (∼9.2 GHz), which suggests that monolayer graphene behaves not as a metal but as a dielectric material.

We fabricated an optically transparent monopole antenna using graphene film and investigated the feasibility of the film as an electrode material for antennas. A low sheet resistance (80 Ω/sq) was attained by stacking the graphene films and carrier doping with an ionic liquid. The optical transmittance of the carrier-doped three-layer stacked graphene film was greater than 90%, enabling it to be embedded in highly transparent objects without altering their landscape. Using the monopole antenna structure with a metal ground plane, we measured the reflection and radiation characteristics of the graphene monopole antenna, excluding the contribution from the power feeding components. The radiation efficiency of the graphene monopole antenna, which was measured by the Wheeler cap method, was determined to be 52.5% at 9.8 GHz. Through the measurements of the graphene monopole antenna, we demonstrated that the carrier-doped three-layer stacked graphene film can be used as an electrode material for optically transparent antennas.

2.1 dB for the backward -z-radiation and 1.5 dB for the forward +z-radiation at 1.580 GHz and 2.230 GHz, respectively. The 3-dB AR bandwidths of about 15 MHz from 1.573 GHz to 1.588 GHz and 17 MHz from 2.223 GHz to 2.240 GHz were about 0.95% for the -z direction and 0.76% for the +z direction. The measured RHCP gain is observed by -4.55 dBic for backward radiation at 1.578 GHz and 0 dBic for forward radiation at 2.228 GHz. | CONCLUSIONThe novel microstrip antenna design method is investigated and demonstrated to reduce the cost and weight of a CubeSat payload. The single arrow-ended cross slot embedded on the ground layer is dually used for the slot antenna fed by the microstrip aperture and the perturbation of the square microstrip antenna. The capabilities of the dual-band bidirectional RHCP at the L1-band and S-band are obtained using a simple design and a single layered substrate. The results demonstrate the proposed antenna may be an excellent candidate for the wireless positioning and satellite communication of a CubeSat system. ORCID Seongmin PyoAbstract A compact wideband bandpass filter (BPF) with broad stopband using hybrid half-mode substrate integrated waveguide (HMSIW) resonator and open-circuit trisection SIRs (OTSIRs) is proposed. A BPF with 3 transmission poles (TPs) and 3 transmission zeros is obtained by cascading the HMSIW resonator and OTSIRs using J and K inverters. A demonstrated wideband BPF with