Micromachined 60 GHz air-filled interdigital bandpass filter

A 4-pole interdigital filter has been demonstrated at 60 GHz with a bandwidth of 10%, it is made using micromachining and a multi-layer bonding. The filter is an airfilled three-dimensional structure. It is formed of five layers which are bonded together. Each layer is micromachined SU-8 based, 200-μm thick, and finished with 1.5 μm gold coating. The resonators are thick stripline-like and enclosed in a cavity. The input and output are transitions from a coplanar structure to a rectangular coaxial line, which are then coupled into the cavity. The filter is only 3.7 mm by 2.0 mm in size and 1.0 mm in height. The measured insertion loss is 1.1 dB and the return loss is below -9 dB. The bandwidth of the tested filter is broadened due to fabrication imperfections, which have been identified by modelling and discussed in the paper

8 pole high temperature superconductor microstrip dual band bandpass filter design

Dual-band filters are normally used for filtering two frequency bands that are not too close together. However, this paper presents a HTS dual-band bandpass filter that can be used to achieve isolation between two frequency bands that are only a few tens of MHz apart. Transmission zeros are placed in between the two frequency bands using electromagnetic coupling between non-adjacent resonators which result in high isolation between the two bands. The simulation and experimental results of a High Temperature Superconductor dual-band bandpass filter with very narrow bandwidth will be presented here

Facing Facts: Facial Injuries from Stand-up Electric Scooters

Background Stand-up electric scooters (SES) are a popular public transportation method. Numerous safety concerns have arisen since their recent introduction. Methods A retrospective chart review was performed to identify patients presenting to the emergency departments in Indianapolis, who sustained SES-related injuries. Results A total of 89 patients were included in our study. The average patient age was 29 ± 12.9 years in a predominantly male cohort (65.2%). No patient was documented as wearing a helmet during the event of injury. Alcohol intoxication was noted in 14.6% of accidents. Falling constituted the leading trauma mechanism (46.1%). Injuries were most common on Saturday (24.7%) from 14h00 to 21h59 (55.1%). Injury types included: abrasions/contusions (33.7%), fractures (31.5%), lacerations (27.0%), or joint injuries (18.0%). The head and neck region (H&N) was the most frequently affected site (42.7%). Operative management under general anesthesia was necessary for 13.5% of injuries. Nonoperative management primarily included conservative orthopedic care (34.8%), pain management with nonsteroidal anti-inflammatory drugs (NSAIDs) (34.8%) and/or opioids (4.5%), bedside laceration repairs (27.0%), and wound dressing (10.1%). Individuals sustaining head and neck injuries were more likely to be older (33.8 vs. 25.7 years, p=0.003), intoxicated by alcohol (29.0% vs. 3.9%, p=0.002), and requiring CT imaging (60.5% vs. 9.8%, p <0.001). Conclusion Although SESs provide a convenient transportation modality, unregulated use raises significant safety concerns. More data need to be collected to guide future safety regulations

New Model for the Effective Permeability of Ferrite Microstrip

This work is to develop a new model for the effective permeability of ferrite microstrips which is based on Wheeler's (1977) microstrip impedance model. The newly developed model for the effective permeability will have some improvements over the well-known model developed by Pucel and Masse (1972). In this model, the transition error (or the discontinuity) from a narrow to wide ferrite microstrip has been removed. Unlike Pucel and Masse's model, where one equation is derived for the narrow ferrite microstrip and another for the wide ferrite microstrip, this model only uses a single equation to predict the effective permeability of the ferrite microstrip for the entire range of widt

Categorising Microstrip Distributed Elements Coupling Types

Coupling coefficient is a very important parameter in the design of RF/Microwave filters. Understanding the coupling mechanism between resonators is very important for achieving a good filter layout. This paper describes a way to classify the type of couplings exhibited in microstrip distributed element resonators. This method explains the coupling types from the definition of coupling coefficients. All the possible coupling types, i.e. electric coupling, magnetic coupling and mixed coupling, will be discussed. The difference between Type-I and Type-II mixed couplings will be addressed. A comparison between the numerically computed coupling coefficients and those computed using computer aided design software is also presented

5-pole High-Temperature Superconductor Bandpass Filter at 12 GHz using High Power TM010 mode of Microstrip Circular Patch

This paper presents a five pole Chebyshev bandpass filter using high temperature superconducting (HTS) thin films which employed the symmetrical TM010 mode of a circular patch resonator. The filter is designed with centre frequency of 12 GHz with fractional bandwidth of 0.45%. The design is fabricated using double sided YBCO thin films on a sapphire wafer of size (0.33×22.5×39.0)mm3. The achieved unloaded Q-factor of the resonators in the fabricated filter is about 6,500 giving the filter an insertion loss of about 0.8 dB at centre frequency of 12.14 GH