International Journal of Electrical and Computer Engineering (IJECE) Vol. 13, No. 3, June 2023, pp. 2600∼2607 ISSN: 2088-8708, DOI: 10.11591/ijece.v13i3.pp2600-2607 ❒ 2600 Two-section branch-line hybrid couplers based broadband transmit/receive switch Ashraf Abuelhaija 1 , Gameel Saleh 2 1 Department of Electrical Engineering, Applied Science Private University, Amman, Jordan 2 Department of Biomedical Engineering, College of Engineering, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia Article Info Article history: Received Jun 1, 2022 Revised Sep 7, 2022 Accepted Oct 1, 2022 Keywords: Harmonic frequency Hybrid coupler Insertion loss Magnetic resonance imaging Transmit/receive switch ABSTRACT This article introduces a broadband microstripline-based transmit/receive switch for 7-Tesla magnetic resonance imaging. The designed switch aims to handle a signal of multiple frequencies to/from a multi-tuned radio-frequency coil that resonates at frequencies corresponding to the speed of precession of a wide range of atomic X-nuclei, at the same time and without tuning. These include 1H, 23Na, 13C, 31P, 19F, and 7Li used in magnetic resonance spectroscopy as a measure to the existence of many diseases. The fundamental and third harmonic center frequencies of the switch are adjusted to resonate at two broadbands cov- ering a wide range of atomic X-nuclei. Two section branch-line hybrid couplers with phase inverters are designed to build the broadband switch. The designed switch used the minimum trace widths of transmission lines that reveal a com- pact size without increasing the heat and then the loss beyond specific values. The couplers and the switch S-parameters exhibited good return loss (<-10 dB), high isolation (<-40 dB), less insertion loss (<1 dB) and two clear wide bands covering many atomic X-nuclei used in diagnosis, at the same time and without the need for any tuning circuit during operation. This is an open access article under the CC BY-SA license. Corresponding Author: Ashraf Abuelhaija Department of Electrical Engineering, Applied Science Private University Amman, Jordan Email: a abualhijaa@asu.edu.jo 1. INTRODUCTION Transmit/receive (T/R) switches in magnetic resonance imaging (MRI) are essential elements when T/R radio frequency (RF) coils are used. They are located between the RF amplifier and the RF coils. The long cables between the power amplifier and the coil as well as the T/R switches add loss to the RF transmitting chain of magnetic for MRI scanner, and thus effect on the power delivered to the transmit coil and increase the noises. The cable loss is reduced by designing power amplifiers of nonmagnetic components near to the magnet bore [1]. Another approach is to design T/R switches that satisfy low insertion loss, high isolation, and good return loss. For single resonant frequency coils, such as 1H protons RF coils, the same single resonance signal must be handled by the switch to the RF coil during transmit and from the coil to the receiver during receive. Similarly, dual and multi resonance T/R RF coils need dual and multi tuned T/R switches, respectively. Magnetic resonance imaging and spectroscopy (MRI/MRS) can provide images with anatomical and metabolic information of the human [2]–[5]. Several studies have shown that non-proton (X-) nuclear imaging can provide valuable information from tissues [6], [7]. For example, 23Na imaging can examine multiple sclerosis and tumors [8], [9]. 31P imaging has been used for assessing healthy human brain, examine breast Journal homepage: http://ijece.iaescore.com