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Switchable design of a frequency reconfigurable broadband whip antenna in high frequency
In this paper, the antenna reconfigurable technology is used to redesign a whip antenna in different sub-bands of high frequency (HF). According to the electrical characteristics of the antenna, on the one hand, two different radiation whip heights are designed to solve the problem of pattern up-warping in the high-frequency band; on the other hand, a common upper loading network and several diffe
MRF volume 13 issue 4 Cover and Back matter
MRF volume 13 issue 4 Cover and Front matter
Rollable metamaterial screen for magnetic resonance coupling-based high-efficiency wireless power transfer
This paper presents a rollable metamaterial screen for high-efficiency wireless power transfer (WPT) system based on magnetic resonance coupling, which operates at 4.5 MHz. The rollable metamaterial screen with a fully expanded area of 750 mm × 750 mm is located in the middle between transmitter and receiver coils and focuses the magnetic field and, by such a way, significantly improves power tran
Compact CPW-fed super wideband planar elliptical antenna
A compact co-planar waveguide (CPW) fed planar elliptical antenna has been designed and presented for super wideband (SWB) characteristics. The designed antenna has an overall size of 30 × 30 × 1.57 mm, and it consists of an elliptical patch radiator fed using a modified 50 ? CPW-fed tapered microstrip feed line. By using a semi-ring shaped structure with a tapered feed line, an impedance bandwidt
Dynamic behavioral modeling of RF power amplifiers based on decomposed piecewise machine learning technique
Multi-device radio frequency power amplifiers (PAs) often exhibit strongly non-linear behavior in combination with long-term memory effects, leading to an extremely challenging model development cycle. This paper presents a new, dynamic, behavioral modeling technique, based on a combination of the real-valued decomposed piecewise method and concepts from the field of machine learning. The underlyi
Analysis and design of inclined fractal defected ground-based circularly polarized antenna for CA-band applications
Design of single-feed circularly polarized (CP) microstrip antenna is proposed in this article. The design employs the concept of E-shape patch with inclined fractal defected ground structure (IFDGS), which can improve the impedance bandwidth, gain, and axial ratio (AR) bandwidth. The excellent enhanced impedance bandwidth, axial ratio bandwidth, and gain are achieved by an inclined E-shaped fract
Compact dual-/tri-/quad-band bandpass filters with independently frequency-tunable and switchable passbands
This paper presents the design of frequency-tunable dual-band, tri-band and quad-band bandpass filters (BPFs). The proposed three BPFs can be independently tuned and individually switched by varying the capacitances of the varactors. In the designed tunable dual-band BPF (TD-BPF), common input/output feed lines are utilized for two tunable dual-mode resonators (TDRs). Further, three TDRs and four
Determining the input reflection coefficient of integrated antennas using over-the-air measurements under near-field conditions
One of the current trends in the integrated circuit (IC) development is the integration of antennas on-chip or in the package of the IC. This poses challenges in the production testing process of the packaged IC, as the antenna functionality has to be included and at least one of the signal ports cannot be accessed at a conducted manner. In order to measure the reflection coefficient of an integra
A planar triple-band monopole antenna loaded with an arc-shaped defected ground plane for WLAN/WiMAX applications
In this paper, a new printed triple-band planar antenna combing two different modified monopoles and an arc-shaped defected ground plane is proposed and studied. The used two simple monopoles consist of a rectangular ring and a rectangular patch attached a straight metal strip. And a compact arc-shaped defected ground structure is proposed and used to excite higher resonance frequency and improve