In this paper, a compact two ports Multiple Input Multiple Output (MIMO) antenna for Ultra Wide Band (UWB) application has been proposed. The presented antenna consists of two symmetrical radiators, developed on an FR4 substrate with an overall size of 34 × 18 × 1.6 mm 3 . The proposed antenna is fed with a 50 Ω microstrip line. The antenna has good impedance matching in the range of UWB band. The isolation is lower than < −15 dB from 3.1 to 5 GHz and < −18 dB from 5 GHz to 11 GHz. Envelope Correlation Coefficient (ECC) < 0.01 and Diversity Gain (DG) > 9.96 dB. The performance of the proposed antenna is analyzed and examined in terms of return loss, gain, radiation efficiency, ECC, DG, and isolation between two ports.
In this paper, we propose a circularly polarized (CP) ultra-wideband (UWB) MIMO antenna. Compared with common linearly polarized (LP) UWB antenna, the proposed antenna can excite circular polarization (CP) mode for WLAN communication and its impedance bandwidth can also fully cover UWB spectrum. It consists of identical circularly polarized antennas. Each unit adopts circular monopole with extended orthogonal rectangle patch to realize broadband and symmetrical rectangular ground with slot in the diagonal of each antenna unit to achieve circular polarization for WLAN band. It has a very compact size and the dimension is 25 × 51 × 0.8 mm3. The impedance bandwidth of the proposed antenna is from 3.1 GHz to 13.5 GHz, with average gain of 4 dBi, fully covering UWB bandwidth and enhanced by 38%. At the same time, circular polarization is achieved by embedding two symmetrical rectangular slot structures in the two opposite corners of every antenna unit. The extended orthogonal rectangle patch is introduced to enhance impedance bandwidth and broaden axial ratio (AR) bandwidth. The measured 3 dB axial ratio (AR) bandwidth is 1.8 GHz (4.7-6.5 GHz), fully covering WLAN band. Meanwhile, the slit slot between antenna units and rectangular openings are introduced to achieve high isolation. The proposed antenna keeps ECC (envelope correlation coefficient) below 0.01, which showing good isolation and diversity characteristics. The proposed antenna can simultaneously operate in the UWB spectrum and exhibit circularly polarized (CP) radiation characteristic in WLAN.
Purpose
This study aims to explore the present status of open-source institutional repository (IR) software’s usage in the university libraries of Islamabad. This study also investigates the views, satisfaction level and challenges of librarians in the adoption and use of IR software.
Design/methodology/approach
A survey was conducted to collect data from the Library Information Science (LIS) professionals working in the university libraries of Islamabad. Data were collected from all library professionals of the Islamabad university libraries by using a structured questionnaire. Out of the total 104 LIS professionals, 84 participated in the study with a response ratio of 80.76%.
Findings
The findings disclose that out of 23 universities recognized by Higher Education Commission (HEC) in Islamabad, 17 (public and private) have developed IRs. Currently, university libraries that have fully implemented the IRs are less as compared with those universities that have partially implemented IR software. However, a good number of university libraries are in the process to develop IRs. Free and open-source software is being used mostly in libraries as compared with in-house developed, locally developed or commercial software. The opinion of librarians about using IR software expressed a positive attitude of librarians. Some of the major challenges encountered by the librarians in using open-source IR software include selection of suitable software and materials for digitization, lack of cooperation from the parent organization, inadequate training opportunities and lack of skilled staff.
Research limitations/implications
This study is geographically limited to the university libraries in Islamabad.
Practical implications
This study will encourage the Pakistani LIS professionals to use open-source software for the development of IRs in their libraries.
Originality/value
This study concludes that the development of IRs in university libraries is a need of the hour. Although the launching of IRs requires certain skills and competencies, Pakistani librarians can overcome these challenges by mastering the ICT skills.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.