Jun Fan

Bio: Jun Fan is an academic researcher from Missouri University of Science and Technology. The author has contributed to research in topics: Equivalent circuit & Printed circuit board. The author has an hindex of 36, co-authored 482 publications receiving 5641 citations. Previous affiliations of Jun Fan include Ulsan National Institute of Science and Technology & University of Missouri.

Dual-Band Directional Slot Antenna for Wi-Fi Application

Abstract: A directional slot antenna with a squared arch structure for Wi-Fi applications is proposed in this communication. In general, one antenna can hardly obtain a nonsplitting and relatively consistent radiation beam in both the 2.4 and 5 GHz bands. A relatively consistent horizontal beamwidth in the dual bands is desired to maintain the same sector signal coverage and avoid interfering with adjacent sectors to maximize the data transmission in usage scenarios such as a sports stadium and warehouse. With a squared arch design, the proposed slot antenna can keep the H-plane beamwidth relatively the same in the dual bands. The slot antenna achieves good matching in both the 2.4 (2.4–2.5 GHz) and 5 GHz (4.9–5.9 GHz) bands, and good vertical polarization. An expression describing the condition of generating a nonsplitting beam is derived as a function of the source spacing, and can be used to guide the arch design. Finally, the proposed slot antenna with the squared arch structure is validated by both simulations and measurements of a prototype.

Analytical intra-system EMI model using dipole moments and reciprocity

Abstract: The dipole moment-based reciprocity to model intra-system electromagnetic interference (EMI) in wireless devices is proposed in this paper. In this model, the decomposition method based on reciprocity is used to calculate the coupling voltage on the victim antenna. The original noise source is replaced by equivalent dipole moments in the forward problem while electromagnetic fields on the locations of dipole moments are scanned in the reverse problem. The proposed model has been validated with full-wave simulations and measurements; it provides not only convenience to estimate radio-frequency interference (RFI), but also physical insight to understand the intra-system EMI problem.

0.7–20-GHz Dual-Polarized Bilateral Tapered Slot Antenna for EMC Measurements

Abstract: An asymmetric wideband dual-polarized bilateral tapered slot antenna (DBTSA) is proposed in this letter for wireless EMC measurements. The DBTSA is formed by two bilateral tapered slot antennas designed with low cross polarization. With careful design, the achieved DBTSA not only has a wide operating frequency band, but also maintains a single main-beam from 700 MHz to 20 GHz. This is a significant improvement compared to the conventional dual-polarized tapered slot antennas, which suffer from main-beam split in the high-frequency band. The innovative asymmetric configuration of the proposed DBTSA significantly reduces the field coupling between the two antenna elements, so that low cross polarization and high port isolation are obtained across the entire frequency range. All these intriguing characteristics make the proposed DBTSA a good candidate for a dual-polarized sensor antenna for wireless EMC measurements.

De-embedding comparisons of 1X-Reflect SFD, 1-port AFR, and 2X-Thru SFD

Abstract: The procedures of lX-Reflect Smart Fixture De-embedding (SFD), 1-Port Auto Fixture Removal (AFR), and 2X-Thru SFD are compared from various perspectives: test fixture design, the de-embedding procedure, and the de-embedded results. The accuracy of the fixture characterization and de-embedded result is the key figure of merit (FOM) in each de-embedding method. Full-wave models were built to evaluate the FOM of these three methods, by comparing the scattering parameters (S-parameters) and TDR. A test coupon for measuring the USB-C cables is adopted to serve as manufactured validation purpose.

Radio frequency interference estimation using transfer function based dipole moment model

Abstract: Dipole moment model is widely used to represent real noise source to estimate near field coupling between noise source and the victim antenna. However, direct full wave simulation of large number of dipole moment is often very time-consuming. Also, another set of full wave simulation is needed if parameters change. A more scalable approach is needed. In this paper, a transfer function based dipole moment model is proposed to solve this issue. The proposed method only needs one-time full wave simulation. The results obtained from this one-time simulation can be reused for other cases if the same antenna structure is used. The proposed method will use the simulation results to construct transfer functions. The method is implemented in CST where several high performance computing methods are available. The validation of a test board with both simulation and measurement data is also provided.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

IEEE Transactions on Microwave Theory and Techniques and Antennas and Propagation Announce a Joint Special Issue on Ultra-Wideband (UWB) Technology

Abstract: Before the emergence of ultra-wideband (UWB) radios, widely used wireless communications were based on sinusoidal carriers, and impulse technologies were employed only in specific applications (e.g. radar). In 2002, the Federal Communication Commission (FCC) allowed unlicensed operation between 3.1–10.6 GHz for UWB communication, using a wideband signal format with a low EIRP level (−41.3dBm/MHz). UWB communication systems then emerged as an alternative to narrowband systems and significant effort in this area has been invested at the regulatory, commercial, and research levels.