Title :
Performance variation in electrical balance duplexers due to user interaction
Author :
Leo Laughlin ; Beach, Mark A. ; Morris, Kevin A. ; Haine, John
Author_Institution :
Dept. of Electr. & Electron. Eng., Univ. of Bristol, Bristol, UK
Abstract :
A key issue impacting the transmit to receive (TX-RX) isolation in Electrical Balance (EB) Duplexers is dynamic matching of the antenna impedance by the balancing network. Circuit simulations including embedded antenna measurements have been used to investigate the variation in TX-RX isolation due to interaction with the user and the local environment. Simulated results at 847MHz and 1960MHz show user interaction causes over 25dB of variation in the mean isolation over a 20MHz bandwidth. However, in reflective indoor environments, user interaction on average improves TX-RX isolation. This observed performance improvement is a result of reduced antenna radiation efficiency, which makes reflections from objects at longer ranges less significant and thereby reduces frequency domain variation in the antenna reflection coefficient.
Keywords :
UHF antennas; antenna radiation patterns; cellular radio; impedance matching; radio transceivers; FDD transceivers; TX-RX isolation; antenna radiation efficiency reduction; antenna reflection coefficient; balancing network; cellular handsets; circuit simulations; dynamic antenna impedance matching; electrical balance duplexers; embedded antenna measurements; frequency 1960 MHz; frequency 847 MHz; frequency domain variation reduction; performance variation; reflective indoor environments; transmit-to-receive isolation; user interaction; Antenna measurements; Bandwidth; Frequency measurement; Impedance; Mobile antennas; Performance evaluation;
Conference_Titel :
Personal, Indoor, and Mobile Radio Communication (PIMRC), 2014 IEEE 25th Annual International Symposium on
DOI :
10.1109/PIMRC.2014.7136182
