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This paper demonstrates structural changes in variable structure control. A second order open loop unstable system was used as an illustrative example to demonstrate the structural changes; the system has real, positive open loop eigenvalues. A change of system eigenvalues implies a change of system structure. A structure may have properties such as being stable or unstable, fast/sluggish response,...
This paper presents a compact antenna design based on PIFA configuration with multi-band features. The present design operates over the lower and upper bands of LTE700/2600MHz, together with the existing standard of GSM1900MHz. An approach of size miniaturization and triple band characteristics was applied through the embedded slot over the radiator surface. The antenna occupies a small volume of...
A printed dipole balanced antenna for mobile phone applications is studied and investigated. This antenna operates in the dual-band of LTE 700/2600MHz. The motivation towards employing a printed folded dipole arms is the reduction in antenna size coupled with wideband capabilities. Partial of the ground was defected by rectangular slot underneath the antenna element to provide the provision for a...
A compact design of balanced antenna operates in the LTE bands of 700/2600MHz is presented. The present antenna is a type of zigzag printed shapes. These zigzag strips were printed over RF4 substrate permittivity of 4.4 and full dimensions of 50 × 11 × 0.8 mm3. The results were simulated, and the performance showed that the zigzag approach was able to enormously reduce the antenna size by a factor...
A new compact dual-band balanced antenna is proposed with meandered lines operating in the LTE bands of 700/2600MHz. It has a compact size with the overall dimensioning of 54×18× 8 mm3, in which can be simply concealed within mobile handsets. Techniques such as meandered lines are used in order to accomplish a well-matching and size reduction of antenna. The meander lines were printed on FR4 substrate...
The small size of the mobile terminal poses serious integration and antenna miniaturization challenges. In this work, we propose a compact dual-band dipole balanced antenna that is based on printed folded arms radiating elements. The performance of the proposed antenna has been analysed and optimised for the two targeted frequency bands in which indicates that a good impedance matching characteristic...
A compact dielectric resonator antenna (DRA) for wideband applications is proposed with a slotted microstrip line antenna. Two cylindrical dielectric resonators, which are asymmetrically located with respect to the center of rectangular coupling aperture, are feds through the aperture of the ground plan. By optimizing the design parameters, an impedance bandwidth of about 46%, covering the frequency...
Researchers at Massachusetts Institute of Technology demonstrated the concept of strongly coupled magnetic resonance (SCMR) in 2007, which was able to transfer energy at mid-range with non-radioactive and high efficiency. Consequently, this signaled a renewed research interest on Wireless Power Transmission within greater scope. Particularly, long range wireless power transmission via microwave has...
In this work, miniaturised tunable two-antenna multiple-input-multiple-output (MIMO) systems composed of printed F-slot shaped are developed to operate in the global positioning system (GPS), personal communication system (PCS), distributed control system and Universal Mobile Telecommunications System bands. The two-element MIMO antenna occupies a volume of 50 × 37.5 × 1.6 mm3, and is printed on an...
A small tuneable MIMO antenna module is investigated for possible UMTS mobile applications. The radiators are realized as slotted planar monopoles. The two-element MIMO antenna module occupies a volume of 50.0 × 37. 5 × 1.6 mm3, and is printed onto a FR4 substrate. Low mutual coupling between the radiators is achieved by means of the addition of a coupling strip to a defected ground plane structure...
In this paper, a compact tuneable F-slot monopole antenna for mobile handset applications, covering the DCS, PCS, and UMTS frequency bands, is presented and studied. An F-shaped slot is embedded in a rectangular monopole patch to accommodate the varactor. The tuning is accomplished by applying DC voltage of varactor diode across the slot arms of the patch .By varying the DC voltage equivalent to capacitance...
A compact PIFLA ultra-wideband (UWB) antenna with a tunable band-notched response is proposed in this paper. Tuning of the rejected frequency is realized by loading an embedded resonant slot with lumped capacitors (equivalent to varactor operation) with capacitance range from 0.75pF to 2.75pF. Antenna prototype was constructed and the measured results show that the proposed antenna can provide an...
Recent research on the performance of multicarrier systems suggest that the us e of wavelet transforms (WT) outperforms the conventional fast Fourier transform (FFT) orthogonal frequency division multiplexing (OFDM) systems. Wavelets based systems provide better spectral efficiency because of no cyclic prefix requirement, have very narrow side lobes and also exhibit improved B ER performance. Meanwhile,...
Without a holistic design and fabrication approach, future wireless communication devices would be extremely large in size to accommodate multiple radio access technologies (RATs) compared to today's more conventional mono-mode devices. Typically multiple RAT devices will be comprised of multiple RF power amplifiers, low noise amplifiers (LNA), RF band pass filters, modulators and demodulators; one...
This paper describes the characterization and design of energy efficient user terminal transceiver power amplifier. To reduce the design of bulky external circuitry, the load modulation technique is employed. The design core is based on the combination of Class B and Class C that includes quarter wavelength transformer at the output to perform the load modulation. The handset transceiver for this...
Fourth generation systems require the use of both amplitude and phase modulation to efficiently utilize the available spectrum and to obtain high data rates, hence imposing stringent requirements on the power amplifier in terms of efficiency and linearity and requires the power amplifier to operate linearly and efficiently. The B3G base station transceiver Doherty power amplifier was designed to operate...
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