Millimeter Wave Measurement of the Low-Loss Dielectric in Vacuum Electronic Devices with Reflection-Type Hemispherical Open Resonator

Abstract

Accurate dielectric properties are of great importance for the design and fabrication of the input and output windows in vacuum electronic devices. A reflection-type hemispherical open resonator (RTHOR) was designed through theoretical analysis and numerical simulation and also was utilized to measure the dielectric properties of the windows material sapphire. Compared with the two ports measurement, a simplified measurement system to obtain the dielectric performance was proposed and the RTHOR with only one coupling aperture was directly connected to a W-band vector network analyzer (VNA). The material properties can be easily calculated through the VNA measured port reflection coefficient (S 11 ) resonant curve. Investigation shows that the permittivity and the loss tangent of the measured sapphire, which is used to construct the input and output window, is respectively about 9.40 and 1.80×10 −4 at room temperature in W-band, which agree well with the reported results. Measured results also show that the simplified measurement system can provide a high accuracy for the measurement of low-loss dielectric in a relatively convenient way.Keywords Reflection-type hemispherical open resonator (RTHOR) . Complex permittivity measurement . Low-loss dielectric . Millimeter wave (mm-wave) . Vacuum electronic devices (VEDs)

A quasi‐optical resonator with new coupling method and parasitic‐mode‐suppressing in 110–170 GHz

“…Based on the above system, we test the fused quartz, and the complex permittivity results are shown in Figure 6. It can be seen that the measured relative permittivity at room temperature is basically consistent with the CRC data [8] (@9.4GHz)3.81,and the literature [1] (@36.18GHz) 3.825, the error is within 2%. The loss tangent is basically in the range of 4E‐04 to 7E‐04, compared with 3.18E‐04 [1] (@36.18GHz).…”

“…It can be seen that the measured relative permittivity at room temperature is basically consistent with the CRC data [8] (@9.4GHz)3.81,and the literature [1] (@36.18GHz) 3.825, the error is within 2%. The loss tangent is basically in the range of 4E‐04 to 7E‐04, compared with 3.18E‐04 [1] (@36.18GHz). The difference in the loss tangent is slightly larger.…”

A Quasi-optical resonator with new coupling method and parasitic-mode-suppressing in 110 ~ 170GHz

“…It can be seen that the measured relative permittivity at room temperature is basically consistent with the CRC data [8](@9.4GHz)3.81,and the literature [1](@36.18G) 3.825, the error is within 2 %. The loss tangent is basically in the range of 4E-04 to 7E-04, comparing with 3.18E-04 [1](@36.18G). The difference in the loss tangent is slightly larger.…”

“…The dielectric properties of microwave dielectric materials are the basis for the integration and development of microwave technology. In the terahertz(THz) frequency range, the open resonator has been widely used in the dielectric constant test of materials due to its advantages of high Q value, no peripheral metal loss and convenient test [1][2]. In this paper, a new coupling method of quasi-optical resonator is designed in the form of coupling plate processed by PCB substrate and pressurized flange in the 110~170GHz frequency band.…”

Microwave Characteristics Analysis of Typical Photosensitive Material InP Under Weak Light Irradiation Based on Quasi-Optical Resonator

“…From [27], modes of TEMplq can be activated in the quasi-optical resonator, and the relationship between the operating frequency f0 of the TEMplq mode and the distance D is given by where c is the light velocity in a vacuum, and p, l, q are the radial, angular, and axial mode index, respectively. The Gaussian beam radius is expressed by where k is the wave vector, z0 is the Gaussian beam radius at z = 0 on the plane mirror, and z0 is given by where λ is the wavelength.…”