摘要
采用双球镜准光腔、频谱仪和锁相返波管组建了D波段低损耗介质测试系统,该系统通过频谱仪和外置谐波混频器得到腔体谐振测试数据,并用拟合或积分方法从谐振曲线中求解出准光腔的品质因数。测得双球镜开腔的固有品质因数大于8×105,使该系统在工作波段可测量损耗角正切为10-5量级的低损耗介质。用该系统测出的石英、人造金刚石和蓝宝石的介电常数和损耗,与报道的结果一致,并测得4H-SiC在132.07GHz的介电常数实部为9.598,损耗角正切为6.1×10-5。
For the determination of dielectric properties of low-loss materials in millimeter wave band, this paper describes a biconcave quasi-optical resonator with the Q factor over 0.8 million, which enables the determination of loss tangents down to the 10^- 5 range. The biconcave resonator system utilizes a phase-locked loop with harmonic mixer to synchronize a backward wave os- cillator source and a microwave spectrum analyzer. The spectrum analyzer acquires high-resolution scan of the resonance curve. The Q factor of the cavity is calculated by performing a non-linear least squares fit to a Lorentzian line shape or by the resonance curve area method. The test results of quartz, CVD diamond and sapphire at ambient temperature are close to the data in the liter- atures, and the permittivity of 4H-SiC at 132.07 GHz are measured to be 9. 598 and the loss tangent to be 6.1× 10 ^-5.
出处
《强激光与粒子束》
EI
CAS
CSCD
北大核心
2012年第2期445-448,共4页
High Power Laser and Particle Beams
关键词
准光学开放腔
锁相返波管
损耗角正切
高功率真空输出窗
Quasi-optical resonator
phase-locked loop backward wave oscillator
loss tangent
high power microwavevacuum output window
