Multi-coupled Lines Research Articles

Coupling Matrix Design of Compact Multiband Cascaded Trisection Bandpass Filters

In this brief, a universal coupled topology to design cascaded multiple passbands bandpass filters (BPFs) with numerous in-band poles and out-band transmission zeros (TZs) is presented. Based on the proposed topology, the coupling matrices are constructed to design multiband bandpass filters (MBPFs) with cascaded trisection (CT) BPFs’ filtering responses. To validate the theory and topologies, a quad-band CT BPFs with TZs located in each lower sub-band is successfully synthesized firstly. Then, a dual-band and tri-band CT BPF with TZs generated in the upper side of each passband are theoretically investigated by employing the coupling matrix. Finally, the proposed dual- and tri-band examples are implemented in compact planar multi-coupled lines structures. In all individual passbands, measured insertion losses (ILs) and measured return losses (RLs) are better than 2.82 dB and 15.9 dB, respectively. Good matching level between the simulated and experimental results have been achieved.

Analytical Design of Dual-Band Negative Group Delay Circuit With Multi-Coupled Lines

This paper develops an innovative design method of a multi-coupled line (CL) topology of low-loss dual band negative group delay (NGD) circuit. The proposed is conceived using three transmission lines (TLs) with different length in which integrate two couplers. The three traveling paths are designed to generate the dual-band NGD effect, where the CLs allow lowering the signal attenuation. The NGD circuit S-parameter model as a function of the TLs physical lengths and coupling coefficient are established. To validate the NGD circuit proof-of-concept, it is fabricated and measured. The NGD values of approximately -4.06 ns and -3.83 ns are measured at center frequencies of 2.43 GHz and 3.02 GHz, respectively. The measured transmission coefficient is better than -2.9 dB and the measured reflection one is better than -12 dB into the NGD band. The measurement results of the NGD circuit are in good agreement with the simulations results.

Analytical Solutions for Distributed Interconnect Models—Part II: Arbitrary Input Response and Multicoupled Lines

In this paper, a new method is presented to calculate the exact analytical solution of distributed RC , LC , and RLC interconnects with a random input at an arbitrary point through the line. The proposed method, based on a modified Duhamel theorem, is used to calculate the time-domain transient response of the initially conditioned interconnects. This method is applied to a line driven by ramp and exponential inputs. The new analytical solutions are expressed as an infinite summation of sinusoidal terms. However, a negligible worst case error of <1% is observed for the expressions compared with HSPICE simulations for Fourier series with tens of terms. In addition, from these results a new model for transient response of a line considering the driver output resistance and capacitance is presented. Good accuracy is observed between the model and HSPICE simulations for various distributed interconnects and drivers. Furthermore, the developed solution is extended to include signal transient and crosstalk noise in multicoupled inductive-effect-prominent lines. In addition, arbitrary switching patterns for identical and nonidentical lines are investigated employing the new method and evaluated with HSPICE simulations.

A Planar Dual 180&lt;formula formulatype="inline"&gt;&lt;tex Notation="TeX"&gt;$^{\circ}$&lt;/tex&gt;&lt;/formula&gt; Hybrid Using Multicoupled Line Sections

A novel planar dual 180° hybrid using multicoupled line technology is presented. The proposed structure adopts the power divider and two types of multicoupled lines to improve the return loss and isolation at the balance outputs of a traditional dual Marchand balun. The proposed hybrid allows output ports to be located arbitrarily, which eliminates the complex layout while the dual 180° hybrid applied to balanced radio frequency circuits. This hybrid is designed and implemented on an FR-4 printed circuit board at 2.4 GHz. The measured return loss is lower than -19.7 dB, and the isolation between the two-pair balanced output ports are lower than -28.2 dB from 2.2 to 2.7 GHz. The measured insertion loss and phase imbalance between the two-pair balanced output ports are lower than 8.7 dB and 4.5°, respectively, at the operating frequency of 2.1-2.9 GHz.

A COMPACT DOUBLE-BALANCED STAR MIXER WITH NOVEL DUAL 180° HYBRID

A compact double-balanced monolithic star mixer for Ka- band applications using 0.25m GaAs pHEMT process is presented. With multi-coupled lines technology, the proposed dual 180 - hybrid is produced and applied to a star mixer successfully. The proposed hybrid adopts the power divider and two types of multi-coupled lines to improve the return loss and isolation at the balance outputs of a traditional dual Marchand balun. Output ports are allowed to locate arbitrarily, eliminating a complex layout while the dual 180 - hybrid is applied to double balanced star mixers. As the measurement results show, the proposed mixer achieves an operation bandwidth of 27 to 36GHz with the best conversion loss of 6.3dB at 28GHz. In addition, the chip dimension can be manufactured as small as 0.81mm 2 .

Compact CAD Models for the Signal Integrity Verification of Multi-Coupled Transmission Lines

A novel modal signal decoupling algorithm for multi-coupled transmission lines is developed. Since the proposed method exploits a set of basis vectors associated with the characteristic impedances of the transmission line system, these multi-coupled signals can be efficiently decoupled regardless of dielectric media and conductors. Thus, compact forms of the signal integrity verification CAD models for multi-coupled transmission lines can be readily determined. It is shown that the analytical models are in excellent agreement with those obtained with SPICE simulation and its computation time is much faster than the conventional macro model (W-model) in the order of two.

THE MINIATURE FREQUENCY DOUBLER USING COMPENSATED CAPACITIVE LINE IN BALUN

A compact balanced frequency MMIC doubler using compensated capacitive line in Marchand balun is proposed. With multi-coupled lines technology, the balun is applied to a balanced doubler successfully. Compared with the conventional Marchand balun, more than 55% reduction in the length of coupled line can be achieved. Implemented by a PHEMT process, the compact monolithic balanced frequency doubler with better performance can be obtained. An operation bandwidth from 20 to 44GHz with the best conversion loss of 8.4dB at 25GHz can be achieved. In addition, the fundamental frequency suppression is better than 28.9dB, and the chip dimension is as small as 0:41 £ 0:68mm 2 .

A MMIC Doubler Based on Novel Open/Short Stub Hybrids

A new configuration of a balanced frequency PHEMT monolithic microwave integrated circuit doubler using open/short stub hybrids is proposed. With multi-coupled lines technology, the phase shifter is produced and applied to a Ka-band doubler successfully. As compared to the conventional lumped-element doubler, this phase shifter can make the doubler more compact in size and flexible in design. The doubler achieves an operation band width of 23 to 26 GHz with the best conversion loss of 7.4 dB at 25 GHz. In addition, the fundamental frequency suppression is better than 24.1 dB, and the chip dimension is as small as 0.85 times 1.1 mm2.

Analytical CAD Models for the Signal Transients and Crosstalk Noise of Inductance-Effect-Prominent Multicoupled $RLC$ Interconnect Lines

Analytical compact-form models for the signal transients and crosstalk noise of inductive-effect-prominent multicoupled lines are developed. Capacitive and inductive coupling effects are investigated and formulated in terms of the effective single-transmission-line model and effective transmission line parameters for fundamental switching modes. Arbitrary switching multicoupled lines are readily decomposed with the fundamental modes by using a symbolic operation, followed by the signal transients and crosstalk noise of multicoupled lines with the closed-form expressions that are derived by using a waveform approximation technique. It is shown that the models have excellent agreement with SPICE simulation.

A Decoupling Technique for Efficient Timing Analysis of VLSI Interconnects With Dynamic Circuit Switching

In today's high-speed/high-density very large scale integrated (VLSI) circuit designs with coupled interconnect lines, signal transients are strongly correlated with the input switching patterns. Signal-delay variations due to the input-switching patterns may be more than /spl plusmn/50% of the delay of an isolated single line. Thus, blind static timing-analysis techniques without consideration of the detailed switching effects may not be accurate enough to meet tight timing margins for today's deep submicron (DSM)-based VLSI circuits. In this paper, the signal-transient responses of multicoupled interconnect lines due to various input-switching patterns are analyzed in terms of the effective capacitances and effective inductances. Thereby, the critical delay line of multicoupled interconnect lines is decoupled into an effective single-isolated line. With the proposed novel decoupling technique for multicoupled interconnect lines, the accurate dynamic delay of strongly coupled interconnect lines can be readily determined with physical layout information. For example, in switching patterns, the paper shows that the signal delays calculated by using the effective single-line models have excellent agreement with SPICE simulations using the generic coupled interconnect circuit models. That is, the accuracy for both RC-dominant lines and RLC lines is within 10% error (but often within 5% error). Thus, without any significant modification of existing IC computer-aided design frameworks, the technique can be directly as well as usefully employed for accurate timing verification of DSM-based VLSI designs.

Analytical models and algorithms for the efficient signal integrity verification of inductance-effect-prominent multicoupled VLSI circuit interconnects

Novel signal integrity verification models and algorithms for inductance-effect- prominent RLC interconnect lines are developed by using a traveling-wave-based waveform approximation (TWA) technique. The multicoupled line responses are decoupled into the eigenmodes of the system in order to exploit the TWA technique. Then, the response signals are mathematically represented by the linear combination of each eigenmode response based on TWA, followed by reporting the signal integrity models and algorithms for the multicoupled lines. The signal integrity of VLSI circuit interconnects is complicatedly correlated with input signal switching-patterns, layout geometry, and termination conditions. It is shown that the technique can be efficiently employed for complicated multicoupled interconnect lines with various termination conditions and the signal transients based on the technique have excellent agreement with SPICE simulations. Thus, with the proposed technique, the switching-dependent signal delay, crosstalk, ringing, and glitches of the inductance-effect-prominent RLC interconnect lines can be accurately as well as efficiently determined.

Novel fast multiline analysis of parasitic effects in CPW inductors for MMICs

The author presents a novel multiline modeling of monolithic microwave integrated circuit (MMIC) spiral inductors in coplanar waveguide (CPW) technology. Starting from transmission line parameters calculated for only single lines and pairs of lines, a distributed equivalent circuit is established for each section of multicoupled lines in the structure. It readily yields the S-parameters of the section. An adequate interconnection of sections having different topologies results in the S-matrix of the device. Our technique is wideband, fast, and fully scalable. It predicts on-line the effect of the underpass and of spurious propagation along the coplanar waveguide (CPW) grounding. It is shown that a significant frequency shift is due to the combination of those two effects. Results are validated by measurements on SOI inductors, up to the second self-resonance frequency.

Simplified Equivalent Representations for Multicoupled Lines and Their Application to Filter Design

This paper preaents simplified lumped-type equivalent representations, which are equivalent to multiwire lines in the vicinity of a quarter-wavelength frequency. It is believed that the derived representation can easily be applied to the analysis and the design of coupled-line filters and directional couplers of narrow bandwidths composed of quarter-wavelength strips. In this paper, the general design methad for coupled-line bandpass filters is presented as one of the applications. A new bandpass filter is proposed and the design formulas of the filter are derived by using the design method. Furthermore the range of validity of the derived representations has been checked by showing numerical design examples. They have been found to give excellent results for coupled-line filters of bandwidths up to about 30 percent.

Optical delay line matched filters

Two multimode optical fibers connected mutually at several locations along their lengths can act as an encoding or decoding structure depending on which terminals are used for the input/output of the data. It is shown that two multicoupled lines have one input which acts as the matched filter for another input, thus enabling easy correlation of data in real time. The performance of such a structure was simulated on a digital computer and the results are discussed.