Compact Printed Dual-band Monopole Array with High Port Isolation

Abstract -In this paper, a compact defected ground structure (DGS) with two circular split ring slots is presented to increase the port isolation of a compact dual-band antenna array. The proposed dual-band DGS is etched on the ground plane between two antenna elements. Each split ring slot corresponds to one resonant frequency of the antenna. The simulated results show that by using the proposed DGS structure the port isolation of the compact array can be obviously increased and the array is suitable for applications in multiple antenna communications. Index Terms -Dual-band array, port isolation, defected ground structure, compact antenna array

Dual-Frequency Two-Element Antenna Array with Suppressed Mutual Coupling

An efficient technique utilizing the defected ground structure (DGS) to suppress the mutual coupling effect of a dual-frequency microstrip antenna array is studied. The proposed dual-frequency DGS beneath two patches includes two circular split ring slots, each of which corresponds to one resonant frequency of the patches. The characteristic of the compact DGS is theoretically and experimentally investigated. The prototypes of the patches arrays with and without the proposed DGS are fabricated. Both the simulated and measured results show that the mutual coupling between array elements has been obviously reduced at the two operating frequency bands with the implementation of the proposed DGS structure

Total hip and knee arthroplasty in HIV- and HCV-positive hemophilia patients: short term follow-up of 14 patients

Abstract Background Haemophilic arthropathy (HA) is a common comorbidity of haemophilia. Some people with haemophilia (PWH) were human immunodeficiency virus (HIV)-positive. Arthroplasty is an effective treatment for end-stage HA. This study was carried out to report the effectiveness and satisfaction following total hip arthroplasty (THA) or total knee arthroplasty (TKA) in PWH with HIV. Patients and methods All patients with haemophilia and HIV undergoing THA or TKA in our centre from January 2015 to June 2020 were reviewed. All patients were followed for at least twenty-four months. The improvements in postoperative indicators were evaluated at the latest follow-up, including the Visual Analogue Scale (VAS) score, range of motion (ROM), and validated joint scores such as Knee Society Score (KSS; clinical and functional) and Harris Hip Score (HHS). The complications and satisfaction were analysed likewise. Those were utilized to weigh the risks and benefits of the procedure in the population. Results Fourteen patients (7 hips and 14 knees) were included in the study. The follow-up of the THA cohort was 53.3 months (range, 27–82) and the TKA cohort was 50.1 months (range, 25–85), respectively. The average VAS score was ameliorated from 7.3 to 3.0 and 6.6 to 2.8 in the two groups (P < .001, respectively). Similarly, two cohorts (THA and TKA) showed statistically significant changes in the extension and flexion ROM between the preoperative and the latest follow-up (P < .05, P < .001, respectively). Besides, statistically significant differences between the preoperative and final follow-up values of HHS (from 41.6 to 82.3), clinical KSS (from 34.8 to 72.8), and functional KSS (from 42.9 to 73.2) were observed (P < .001, respectively). Notably, there were 4 complications noted among 21 arthroplasties performed, giving a 19.0% complication rate. Based on the satisfaction score, the majority of patients were optimistic about the arthroplasty. Conclusion Given these findings, THA or TKA of the PWH with HIV is a worthwhile procedure and can be performed by an experienced and collaborative multidisciplinary team in a tertiary centre with a good haemophilia care system