A novel wideband power divider with ultra‐wideband suppression of harmonics is proposed in this paper. The power divider is composed of double‐sided parallel spoof surface plasmon polaritons transmission line (DSP‐SSPP‐TL) with periodical grooved bow‐tie cells. The cut‐off frequency of DSP‐SSPP‐TL can be flexibly adjusted by changing the parameters of bow‐tie cells. To demonstrate that, dispersion relations of the bow‐tie cells with different parameters are simulated, and three DSP‐SSPP‐TL counterparts are experimented. Then, a power divider centered at 3.31 GHz (f0) is designed, fabricated, and measured. Experimental results indicate that the 10‐dB return loss bandwidth of the proposed power divider is about 146% from 0.9 to 5.73 GHz, and the upper stopband is extended up to 40 GHz (12.1 f0) with the suppression level above 32 dB. Moreover, ultra‐wideband isolation between two output ports of the proposed power divider could be achieved by employing two lumped resistors between two DSP‐SSPP‐TLs.
Abstract:A novel miniaturized-element frequency selective surface (MEFSS) providing a second-order bandpass response was presented and experimentally verified. The proposed structure consists of sub-wavelength inductive wire grids and a hybrid resonator composing of a two-dimensional periodic arrangement of miniaturized Jerusalem slots etched into a ground plane, which produces a miniaturized unit cell. The full-wave and equivalent circuit model simulations were performed. A prototype of the proposed second-order bandpass FSS was also fabricated and tested using a free-space measurement setup. The measurement results of this device exhibited a stable frequency response with respect to the angles of incidence up to 45°.
Electrical connectors are widely used in electrical devices as an interconnect element and their reliability is a critical factor in device performance. However, there are multiple factors that may lead to poor reliability. These include contact failure induced by temperature and humidity, vibration, and atmospheric contamination, which may induce deterioration of the transmitted signal and leakage of electromagnetic energy. In the current work, the contact failure characteristics of a specific connector are investigated through measurement and analysis of high frequency parameters and spectrums. Based on transmission line theory and electrical contact theory, an equivalent model was developed to explore the effect of contact failure on high frequency parameters. Experiments were conducted using a network analyzer, signal generator, signal analyzer, and H‐field probe. The high frequency parameters were measured and compared with the calculated values, with consistent results. The leakage spectrums were measured with an H‐field probe for a variety of input signal amplitudes and frequencies and loose contact conditions. The results indicate that leakage increases with higher frequency and greater input signal amplitude.
The factors affecting the re-orientation accuracy of the on-orbit replaceable optical unit were studied, and the mathematical models of the relationships between fit clearances of positioning mechanisms and the limits of rotation angles were deduced. When the relative position relationship of positioning mechanisms was determined, fit clearances were designed according to the requirement of the rotation angle limits, and the rotation angle limits were determined to ensure that the angles were within the index range. Theodolites were used to measure the re-orientation angles of the optical unit, and the errors between the measurement angles and the real angles were deduced. Then, the numerical simulation proved that the errors were within limits. The microgravity test environment was established, and the weight of the optical unit was unloaded by a suspension method to simulate the state of the optical unit when it was replaced on orbit. The test results confirmed the correctness of the design method.
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