Browsing Engineering and Informatics by Author "Abdulkhaleq, A.M."
Multi-Resonant Class-F Power Amplifier Design for 5G Cellular NetworksSajedin, M.; Elfergani, Issa T.; Rodriguez, J.; Violas, M.; Asharaa, Abdalfettah S.; Abd-Alhameed, Raed A.; Fernandez-Barciela, M.; Abdulkhaleq, A.M.This work integrates a harmonic tuning mechanism in synergy with the GaN HEMT transistor for 5G mobile transceiver applications. Following a theoretical study on the operational behavior of the Class-F power amplifier (PA), a complete amplifier design procedure is described that includes the proposed Harmonic Control Circuits for the second and third harmonics and optimum loading conditions for phase shifting of the drain current and voltage waveforms. The performance improvement provided by the Class-F configuration is validated by comparing the experimental and simulated results. The designed 10W Class-F PA prototype provides a measured peak drain efficiency of 64.7% at 1dB compression point of the PA at 3.6GHz frequency.
Recent developments of reconfigurable antennas for 4G and 5G wireless communications: A surveyOjaroudi Parchin, Naser; Basherlou, H.J.; Al-Yasir, Yasir; Abd-Alhameed, Raed A.; Abdulkhaleq, A.M.; Noras, James M. (Avid Science, 2019-12)Reconfigurable antennas play important roles in smart and adaptive systems and are the subject of many research studies. They offer several advantages such as multifunctional capabilities, minimized volume requirements, low front-end processing efforts with no need for a filtering element, good isolation, and sufficient out-ofband rejection; these make them well suited for use in wireless applications such as fourth generation (4G) and fifth generation (5G) mobile terminals. With the use of active materials such as microelectromechanical systems (MEMS), varactor or p-i-n (PIN) diodes, an antenna’s characteristics can be changed through altering the current flow on the antenna structure. If an antenna is to be reconfigurable into many different states, it needs to have an adequate number of active elements. However, a large number of high-quality active elements increases cost, and necessitates complex biasing networks and control circuitry. We review some recently proposed reconfigurable antenna designs suitable for use in wireless communications such as cognitiveratio (CR), multiple-input multiple-output (MIMO), ultra-wideband (UWB), and 4G/5G mobile terminals. Several examples of antennas with different reconfigurability functions are analyzed and their performances are compared. Characteristics and fundamental properties of reconfigurable antennas with single and multiple reconfigurability modes are investigated.