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Thin film copper membranes on silicon substrates were constructed using micromachining techniques. Membranes were used as flexible ground planes beneath a microstrip transmission line. Actuation of membranes induced phase shift in the transmitted signal. Membranes possessed radial surface corrugations 10 μm deep to increase their flexibility. Membranes were released using a combination of KOH and...
This paper presents an eigenfunction solution for a transverse magnetic (TM) normal incident plane wave on a chiral elliptic cylinder. The solution is expressed in terms of vector wave functions with unknown expansion coefficients. The coefficients are determined by matching continuity of the tangential components of electric and magnetic fields at the chiral elliptic cylinder surface.
This paper presents a microstrip ring resonator design which exhibits suppressed harmonic excitation and high quality factor. The resonator is constructed from four quarter-wave coupled-line couplers, connected in a square configuration. Of interest is the change in the frequency response of the ring when corrugated couplers are used in place of ordinary couplers. By direct comparison it is shown...
Turbo Codes have been an attractive topic in coding theory community since they were introduced in 1993 due to their powerful error correcting capability and superior coding gain. Thanks to their astounding performance, Turbo codes are used in 3rd generation wireless communication and satellite communication system. Fore these applications, efficient implementation of Turbo Codes, i.e., development...
Since the introduction of the Asymptotic Waveform Evaluation algorithm [1], model order reduction techniques have shown high computational efficiency for fast solution of large interconnect problems. The reduced-order models of linear interconnect networks can be derived by matching network moments via Padé approximations. For interconnect networks containing distributed transmission lines, the associated...
Recently, there has been extensive research on the photonic band gap structures (PBG's) and their applications in the microstrip antennas and transmission lines. The PBG structures have the unique property of preventing the propagation of EM waves in certain directions for certain frequencies. The properties of these structures are defined by the shape, size, symmetry and, the constituent material...
An overlay structure broadband CPW coupler has been realized at millimeter-wave frequency and the size is only one third of the Lange coupler with same performance. It was used to construct a BPSK modulator employing balanced reflection topology with HBTs acting as switches. The modulator showed ±0.2dB amplitude imbalance and ±2° phase error over 26.5∼30.5GHz.
In this paper, Serial Concatenated Convolutional Code (SCCC) with Continuous Phase Modulation (focus on MSK) and Log-MAP decoding algorithm is investigated. As an alternative solution to Parallel Concatenated Convolutional Code (PCCC), which is termed Turbo Code (TC), SCCC is in some cases superior to that of TC with similar complexity, especially at high Signal-to-Noise ratio. SCCC consists of a...
Microstrip antennas are known for their advantages in lightweight, low volume, low cost, and compatibility with integrated circuits. These advantages make this antenna a useful candidate in applications such as mobile radio, satellite communications, biomedical radiators and feed elements for reflectors. An important factor in the performance of microstrip patch antennas is the ground plane. The size...
A typical multimedia via satellite mission needs to cover, from a geostationary orbit, a large terrestrial zone with 40 to 50 semi-contiguous beams, for very high gain & re-using 10 to 12 times the same frequency resource, by dividing the available bandwidth in 4 sub-bands, 1 spot-beam over 4. Such multibeam antenna much increases the System capacity, for providing broadband services directly...
It has been common practice for several decades to fit private cars and commercial vehicles (such as taxi, police car) with radios or two-way communication devices. The mobile antenna for cars has been widely studied and somehow mature, such as whip antenna, invert-L antenna and loop antenna [1], [2], [3].
A new efficient method-method of moment (MOM) with modal expansion-has been developed to analyzed multilayers dielectric resonators (DR) loaded cavities. The resonant frequencies, convergence, and field distributions are presented. Also the efficiency and accuracy of this new method have been verified.
In this paper the RF delay line is used as the beam-forming network to generate eight beams for giving antenna array aperture. There are eight beam patterns from the eight antenna elements in this MBA (Multiple Beams Antenna) system. The eight antenna elements are the coaxial collinear antennas with quarter wavelength above the ground plane. The beamwidth for these eight beams are changing from 10°...
Low temperature co-fired ceramic (LTCC) is a multilayer material used for system packaging. It offers many advantages in high density integration for RF to millimetre-wave integrated circuits [1]. It is therefore an attractive technology for packaging phased array modules, where the size is an important issue especially at millimetre-wave frequencies [2]. The circuits realised with other processes,...
General unsymmetric systems of linear algebraic equations are modeled by linear electric circuits using a procedure previously developed for symmetric systems [1]. Augmented symmetric systems are constructed from the original unsymmetric ones and then the modeling technique based on the node-voltage method is applied. The unknowns of a system of equations are simply obtained by measuring the nodal...
Over the last few years the demand for wireless communication services has been risen beyond expectations. The operation of wireless communication is subject to limited available spectrum, thus, how to improve frequency reuse efficiency is important. Spatial division multiple access (SDMA) scheme is another mean, besides that of TDMA, FDMA and CDMA, to expand channel capacity to meet the escalating...
In satellite mobile communications, TWT (Traveling Wave Tube) amplifiers are used to increase power efficiency. Unfortunately, power-efficient amplifiers cause nonlinear distortions to the transmitted signal These distortions make the received symbols no longer on the original regular lattice but on a warped one. Several authors use analytical models (such as Saleh model) to describe both amplitude...
In Satellite ATM (SATM) networks, the various traffic patterns and dynamically changing topology call for effective network traffic control mechanisms to reduce congestion and utilize network resource efficiently. There are two major challenges in the SATM traffic control. On one hand, the time varying traffic arises big challenges for guaranteed service in ATM. On the other hand, due to the permanent...
This paper presents a general method combining microwave empirical/equivalent model with artificial neural networks for efficient modeling of microwave components. The method, called Generalized Knowledge-Based Neural Network (GKBNN), unifies several existing methods and provides increased model accuracy and extrapolation capability, even if the training data is limited. It is applied to microwave...
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