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A reconfigurable bandpass filter with compensable coupling and constant absolute bandwidth (ABW) is proposed. The fundamental structure is based on two coplanar waveguide (CPW) resonators and a microstrip-to-CPW transition. Four varactors embedded in the resonators and feed-lines are utilized to adjust center frequency and external coupling, separately. Moreover, this novel feeding structure generates...
Mobile terminals are required to cover wide range of RF frequencies for the enhancement of mobile communication systems. Thus reconfigurable RF circuits for the terminals attract much attention because they flexibly change many frequency bands under the control of the communication systems. Reconfigurable bandpass filter (BPF) with eight-frequency selection capability has been studied for this goal...
By using λ/4 coupled-line section to take place conventional λ/4 transmission line, a Wilkinson power divider with band-pass filter response and easy structure is presented in this paper. Design equations for characteristic impedances are derived from even- and odd-mode analysis. Design chart, frequency responses and several design examples are presented; the 3dB bandwidth is also discussed in this...
A broadband double negative media (DNG) is proposed and investigated theoretically in this paper. The top view of structure proposed in this paper is a combination of ellipses with minor axis at 6 mm and major axis at 16 mm, rotating 45 degrees each time. The combination of ellipses is a gradient structure at the boundary, so that there are strong superposition of coupling between each two ellipses...
This paper presents a dual-band quadrature coupler with a cascaded coupled-line structure. Conventionally, the parallel coupled lines with an electrical length of 90° only operate at a single frequency. The proposed design achieves dual-band operation by cascading three coupled-line sections with appropriate electrical lengths, which has the advantage of high frequency ratio. The design strategy was...
A broadband balun with the compensated coupled line at balanced ports has been proposed. The operating fractional bandwidth of the proposed balan is 10% more than that of the conventional Marchand balun. Moreover, the proposed method can be employed for a long connecting segment between the balanced ports with tight coupling at desired frequencies. In addition, summarized graphs are provided as well...
A novel design of the probe intended for application in multiprobe reflectometer is proposed. It is realized as a connection of short weakly-coupled-line sections and a lumped resistor and provides flat coupling characteristics over a very wide frequency range. The developed probe has been utilized in the design of a multiprobe reflectometer operating within the bandwidth 0.15–8 GHz. The measurements...
This paper presents an electric coupling structure based on double-layered SIW cavity resonators which provides enhanced coupling coefficient. Electric coupling is achieved by inserting two short-ended striplines between two SIW cavities. The electric coupling depends on the width of the stripline. The proposed structure can achieve coupling coefficient more than 0.12. In order to validate the proposed...
The wireless system with four coil resonators is a popular configuration for mid-range wireless power transfer via magnetic resonance coupling. The locations of four coils have strong impact on efficiency, resonant frequency and bandwidth of the wireless power transfer system. In this work, a comprehensive study on frequency effects of coil location parameters, such as the distances between neighboring...
This work describes two methods for improving the directivity of an edge coupled microstrip based coupler with weak coupling. The proposed couplers have a coupling factor of about −30 dB. The coupler with interdigital capacitors achieved for excess loss of 0.5 dB a fractional bandwidth of 44 % and directivity of 25 dB. The second structure uses floating stubs between the coupled lines, which increases...
Wide-I/O dynamic random access memory (wide I/O DRAM) is one of promising solutions to increase the memory bandwidth. Similar to modern double-data-rate DRAMs, the minimum burst length of wide I/O DRAM is at least two. Thus, either a read or a write operation is executed, two words will be read or written at least each time. This causes that the testing of inter-word coupling faults becomes complicated...
Partial discharge (PD) is the main cause of the failure of power apparatus insulation. The detection of PD in the early stage is useful to understand the condition of power apparatus, to design predictive maintenance program, and to prevent the breakdown of power apparatus. PD signal can be detected by the sensor. This paper deals with design of resistor capacitor (RC) circuit as PD detector. The...
a simple microstrip UWB antenna with dual band- notch function is presented. The antenna consists of a square patch and a partial ground plane. For expanding the impedance bandwidth, H-shaped slot on the ground plane is etched. Also, to obtain two notched bands, S-shaped coupling element and an inverted L-shaped arm ended up a shorting pin are utilized. The antenna has a compact size of 15×22 mm2...
The next generation of small cell base stations (SCBSs), with multi-mode specialty, can offload part of traffic load to unlicensed spectrum to alleviate burden in licensed band. In this paper, we propose an interference graph to capture the coupling interference relationship in unlicensed band between small cell. Based on the interference graph, we formulated the traffic-offloading issue as the local...
We present modeling and computer simulation of the intensity noise in VCSELs with a transverse-coupled cavity (TCC). The dynamics and noise TCC-VCSELs are characterized in the three states of operation; namely, continuous wave (CW), pulsing and chaos depending on the coupling ratio between the VCSEL and feedback cavities. The intensity noise is evaluated in terms of the frequency spectrum of the relative...
We performed the modeling on the modulation bandwidth of transverse-coupled-cavity VCSELs by using coupled mode theory. The simulation shows the 3dB-modulation bandwidth can be doubled under out-of-phase coupling between the two cavities.
Phononic crystals (PCs) commonly consisted of two materials with huge contrasted elastic properties and mass densities. In this paper, the propagation of Lamb waves in the composite PCs is investigated. Coupling effects of band gaps for low order Lamb wave modes are found. Crucial parameters such as the periodical arrangement of the scatterers are discussed in detail for the influence of band structures.
The design of a fundamental rectangular-to-circular coaxial cavity input coupler for a low-THz gyro-traveling wave amplifier (TWA) is presented. Theoretical and numerical approaches to the design of the coaxial cavity input coupler are introduced. The design is optimized for operation between 360–384 GHz, achieving a transmission bandwidth of 7.5% (358–386 GHz). A comment on the manufacturability...
A novel type of strong-coupling five-gap extended output cavity is investigated for the W-band SBEIK to verify its resonant advantages of mode separation, gap fields coupling and RF energy exporting etc. And the degeneracy mode competition for the strong-coupling five-gap cavity is studied due to its axial period structures. The result shows that the frequency interval between the work mode and vicinal...
Fully-etched cladding-modulated grating allows not only flexible control of the reflection response but also large fabrication tolerance. A reflection bandwidth of < 0.6 nm and a Bragg wavelength variation of within 1 nm is experimentally demonstrated.
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