Base Station Antenna with Enhanced Cross Polarization Discrimination Performance by Using Horizontal Meandered Dipole and Vertical Parasitic Elements

This study is related with the design of a ± 45° dual polarized base station antenna with improved cross-polarization discrimination (XPD) values. Parasitic elements are added to antenna design formed by orthogonal two compact meandered dipole above ground plane. The antenna designed with CST Microwave Studio program has VSWR ≤ 2 within 1.71-2.69 GHz frequency band, which covers GSM 1800/3G/LTE bands. The antenna has minimum of 0 dBi gain in the beamwidth of 120° ( 60°) at azimuth plane (ϕ = 0°) along the band, and XPD values being minimum of 2 dB at 1.71-2.4 GHz for  60° without parasitic elements are improved to 10 dB with parasitic elements. This design initially had two horizontal straight monopoles on the ground plane perpendicular to each other. Afterwards, antenna with microstrip balun feed applied but the XPD values were not appropriate to expected results. Because of that, by using image theory, vertical parasitic elements were added to get appropriate XPD values. Later, meandered structure used to make antenna smaller. Finally, according to base station applications, antenna frequencies optimized to 1.71 GHz and 2.69 GHz. The designed and optimized antenna produced and measured in laboratory environment. Return losses for port 1 and port 2 are measured above the 10 dB and isolation between the port 1 and port 2 are measured above the 20 dB. In addition, the maximum gain values are measured between 3 dB and 7 dB in 1.71 GHz and 2.69 GHz frequency band.  Finally, XPD values are measured more than 10 dB in bandwidth

Medicinal plants popularly used in the villages of Yunt Mountain(Manisa-Turkey)

PubMed ID: 17878061A survey carried out during the years 2001-2002 revealed that people who lived in the villages of Yunt Mountain use large number of plants for medicinal purposes. Fifty-four medicinal plants belonging to 32 family were recorded. Among them 41 species were wild and 13 species were cultivated plants. © 2007 Elsevier B.V. All rights reserved

Ecology of Dispersal Systems In Polymorphic Seeds of Camellia In Japan

WOS: A1982PR2930000