Browsing by Author "Bakirli, Yigit"

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Citation - Scopus: 5
Broadband Compact Quasi Yagi Antenna for UHF Wireless Communication Systems with Enhanced Performance at UHF ISM Bands
(SPOLECNOST PRO RADIOELEKTRONICKE INZENYRSTVI, 2020) Yigit Bakirli; Ali Selek; Mustafa Secmen; Selek, Ali; Secmen, Mustafa; Bakirli, Yigit
In this study a broadband planar quasi Yagi antenna operated at ultra-high frequency (UHF) band is presented. The performance of the antenna is particularly improved for two popular UHF frequencies of 433 and 868 MHz used in several wireless communication applications such as Long Range (LoRa) Internet of Things (IoT) Machine-to-Machine (M2M) Wireless Meter bus (M-bus) and Radio Frequency Identification (RFID). The proposed antenna includes a printed feed dipole with a ground reflector and two parasitic (director) elements on a substrate to keep total dimensions of the antenna within compact size. The parasitic elements are very thick and closely spaced to feed dipole. Significant increase in the bandwidth is obtained with the improved effects due to usage of tapered feed line and tapered reflector. The antenna's 10-dB return loss bandwidth is measured more than 70% between 428 MHz and 896 MHz. The antenna offers moderate peak gain values of 5.5 dBi and 5 dBi, and front-to-back ratio (F/B) values of 12 dB and 14 dB at lower and higher parts of UHF band around 433 and 868 MHz respectively. The peak gain and F/B ratio values are found to be minimum 4 dBi and 8.5 dB within the operating bandwidth respectively.
Citation - WoS: 3
Citation - Scopus: 5
Printed Quasi Yagi Antenna with Closely Spaced and Thick Directors for Triple ISM-Band/Wideband Applications at UHF
(IEEE, 2018) Ceyhan Turkmen; Yigit Bakirli; Mustafa Secmen; Mehmet Altuntas; Secmen, Mustafa; Turkmen, Ceyhan; Bakirli, Yigit; Altuntas, Mehmet
In this study a printed quasi Yagi antenna realized for almost whole UHF band is given. Within overall UHF band the performances of three well-known ISM frequencies of 433 866 and 915 MHz which are used in many wireless applications such as LoRa IoT M2M M-bus and RFID are desired to be kept relatively better. The proposed antenna includes a printed feed dipole with reflector and two director elements. The directors are quite thick and closely spaced to feed dipole which provides significant enhancement in the bandwidth. According to gathered results the antenna has more than 80% bandwidth for S11 < -6.5 dB between 407 and 955 MHz where return loss values are higher than 10 dB in the bands 417-493 MHz and 700-920 MHz covering three mentioned UHF ISM bands. Additionally it has more than 10 dB front-to-back ratio and 4 dBi realized gain for the frequencies lower than 500 MHz and higher than 850 MHz which again includes 433/866/915 MHz bands, while the gain values in the remaining band are relatively low as being 3.5 dBi on the average.