Coupled-resonator Network Research Articles

A Ka-Band Broadband Power Amplifier With Transformer-Based Lossy Magnetically Coupled Resonator Network: Analysis and Design

A <i>Ka</i>-Band Broadband Power Amplifier With Transformer-Based Lossy Magnetically Coupled Resonator Network: Analysis and Design

Modularizing Coupled-Resonator Networks: Leveraging Two Primary Operations

Modularizing Coupled-Resonator Networks: Leveraging Two Primary Operations

High-Gain Third-Order Filtering Patch Antenna Array With Two Radiation Nulls Using Cross-Radiation

A compact third-order filtering antenna array with high gain and two controllable radiation nulls is proposed. The antenna consists of one narrow patch in the center fed by the coaxial port and four wide patches placed around it. Four shortend stub-loaded resonators are capacitively coupled between the center patch and the outer patches, which makes the radiated Efields of the center patch and the outer patches in-phase at the center frequency of the passband to realize the high gain and outof-phase at the low and high stopbands to introduce a pair of radiation nulls. The working principle of the filtering antenna array can be explained by the coupled-resonator network. Finally, a filtering antenna array centered at 3.5 GHz with a fractional bandwidth of 4.26%, a high maximum gain of 12.2 dBi, high out-of-band selectivity, and wide stopband is designed, fabricated, and measured.

A 124-to-152-GHz Power Amplifier Exploiting Chebyshev-Type Two-Section Wideband and Low-Loss Power-Combining Technique in 28-nm CMOS

This article presents a high-power wideband power amplifier (PA) with a four-way power-combining technique for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$D$</tex-math> </inline-formula> -band high-resolution radar. The power combiner is based on a two-section Chebyshev impedance converter to achieve a large bandwidth (BW) and is realized with slow wave coplanar waveguides (S-CPWs) to reduce the insertion loss and chip area. Therefore, our developed technique can provide broadband and low-loss power-combining scheme in a very compact size. A high-power PA with four-way combining has been fabricated in a 28-nm CMOS bulk technology. The unit PA uses low- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$k$</tex-math> </inline-formula> transformer-based coupled-resonator networks to realize wideband matching. The measured results of the PA prototype demonstrate the peak gain of 22.6 dB, the saturated output power of 16.2 dBm, and the peak power added efficiency of 8.6% at 135 GHz with a 3-dB BW of 28 GHz from 124 to 152 GHz. Meanwhile, the total area of this PA die is merely 0.66 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times$</tex-math> </inline-formula> 0.73 mm.

RF Multi-Functional Input-Reflectionless Dispersive-Delay Structure With Sharp-Rejection Filtering Using Channelization Techniques

A class of RF multi-functional input-reflectionless dispersive-delay structure (DDS) with linear-type in-band group-delay variation and sharp-rejection bandpass-filtering capability is reported. It exploits a two-branch-channelized/balanced-type circuit with similar low-order reflective DDS units inside its channels, which are connected through input/output 3-dB quadrature wideband couplers. The adopted DDS unit is based on a coupled-resonator network with a frequency-dependent cross-coupling. It introduces a pair of complex transmission zeros (TZs) to shape the intended in-band group-delay profile. Unequal transmission-line-based phase-shifting sections are also inserted at the outputs of both channels. In this manner, an input-absorptive behavior and selectivity enhancement with TZ generation are attained by means of transversal signal-interference techniques at the overall input and output nodes, respectively. Moreover, as the transfer-function phase term of the interference action in transmission is linear with frequency, the total group-delay pattern is defined by the DDS unit of the channels. As practical validation, a 1.5-GHz proof-of-concept microstrip prototype is constructed and tested.

Phase De-Embedding of Narrowband Coupled- Resonator Networks by Vector Fitting

This paper introduces a simple and effective way to de-embed the constant phase loading and transmission line from the simulated or measured S-parameter data of a narrowband coupled-resonator network by vector fitting. The phase-corrected S-parameters can be converted to Y-parameters to prepare for rational function approximation and extraction of the coupling matrix for the purpose of computer-aided tuning. This method is applicable to many narrowband coupled-resonator networks including microwave bandpass filters and diplexers. Examples including a simulated triple-mode bandpass filter and a measured wire- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${T}$ </tex-math></inline-formula> junction diplexer are given to demonstrate the effectiveness of the new technique.

Non-local scattering control in coupled resonator networks.

We demonstrate scattering control of Gaussian-like wave packets propagating with constant envelope velocity and invariant waist through coupled resonator optical waveguides (CROW) via an external resonator coupled to multiple sites of the CROW. We calculate the analytical reflectance and transmittance using standard scattering methods from waveguide quantum electrodynamics and show it is possible to approximate them for an external resonator detuned to the CROW. Our analytical and approximate results are in good agreement with numerical simulations. We engineer various configurations using an external resonator coupled to two sites of a CROW to show light trapping with effective exponential decay between the coupling sites, wave packet splitting into two pairs of identical Gaussian-like wave packets, and a non-local Mach-Zehnder interferometer.

Non-classical light state transfer in su(2) resonator networks

We use a normal mode approach to show full and partial state transfer in a class of coupled resonator networks with underlying su(2) symmetry that includes the so-called J_{x} photonic lattice. Our approach defines an auxiliary Hermitian coupling matrix describing the network that yields the normal modes of the system and its time evolution in terms of orthogonal polynomials. Our results provide insight on the full quantum state reconstruction time in a general su(2) network of any size and the full quantum transfer time in the J_{x} network of size 4 n + 1 with n=1,2,3,ldots For any other network sizes, the Fock state probability distribution of the initial state is conserved but the amplitudes suffer a phase shift proportional to pi /2 that results in partial quantum state transfer.

Dispersive Delay Structures With Asymmetric Arbitrary Group-Delay Response Using Coupled-Resonator Networks With Frequency-Variant Couplings

This article reports the design of coupled-resonator-based microwave dispersive delay structures (DDSs) with arbitrary asymmetric-type group delay response. The design process exploits a coupling matrix representation of the DDS circuit as a network of resonators with frequency-variant couplings (FVCs). The group delay response is shaped using complex transmission zeros (TZs) created by dispersive cross-couplings. We also present an optimization-based synthesis procedure for characteristic polynomials with a prescribed group delay profile. Thus, when compared with prior-art DDS approaches, the proposed DDS solutions allow a general group delay profile to be patterned while incorporating optimization-based coupling matrix design techniques for their synthesis. The design method is validated by full-wave simulations and measurements of three built proof-of-concept prototypes of DDS devices with different shapes of group delay response in waveguide and microstrip technologies.

Phase Adjustment of S-Parameters from Coupled Resonator Filters

This paper presents a method to cancel the constant phase loading and transmission line that are added to the S-parameters of coupled resonant networks. Thus, the phase-corrected S-parameters may be used to obtain a rational model together with its representative coupling matrix. This method is applicable to lossy and lossless coupled resonator networks with two ports, such as microwave filters. In addition, it has the advantage of not requiring S-parameters with wide frequency ranges, and offers less computational effort than other approaches. Examples including simulations of microwaves passband filters are provided in order to demonstrate the effectiveness of this new technique.

Coupling Matrix Synthesis of Microwave Differentiators

This letter presents a new design of microwave differentiators using coupled-resonator network. It is synthesized using coupling matrix techniques in the low-pass domain and subsequently transformed and implemented in the bandpass domain. Two numerical examples and one experimental validation are provided to illustrate the approach, which finally validates the proposed approach.

Magnetless Microwave Circulators Based on Spatiotemporally Modulated Rings of Coupled Resonators

Nonreciprocal components are ubiquitous in electronic and optical systems. To date, the use of magneto-optical materials has been the prevailing method to achieve nonreciprocity. However, magnetic-based devices are accompanied by several drawbacks, such as the requirement of bulky biasing devices and their incompatibility with semiconductor technology, which make their integration challenging. Recently, strong magnetless nonreciprocity was demonstrated in spatiotemporally modulated coupled-resonator networks as a result of an effective spin imparted to the structure by an RF signal. These structures can be easily integrated, and they potentially exhibit good power and noise performance, as any parametric device. Here, we develop an analytical theory for such devices, which allows determining the conditions for designing them with optimum characteristics, and present two designs based on lumped- and distributed-element circuits for applications at the very high-frequency and wireless-communications bands, respectively. The circulators exhibit large isolation and low insertion loss within reasonable modulation requirements. Furthermore, they can be realized with a modulation frequency substantially lower than the input frequency, significantly simplifying the design. Measurements for the lumped-element design are provided and show good agreement with theory and full-wave simulations. The nonlinear characteristics of the presented designs are also studied, and possible ways to reduce nonlinear distortion by increasing the static bias of the varactors or using advanced varactor topologies are explored.

Compact substrate-integrated waveguide bandpass rat-race coupler and its microwave applications

A reduced size rat-race coupler incorporating a bandpass frequency response characteristic is presented and designed based on substrate-integrated waveguide (SIW) technology. By use of electric- and magnetic-coupling structures between adjacent SIW cavity resonators, a conventional rat-race coupler and a bandpass filter with a 200-MHz bandwidth at a centre frequency of 7.75 GHz can be integrated as one component resulting in miniaturisation. A design process based on the coupled-resonator network is introduced to synthesise such a bandpass coupler with desired bandwidth, return loss and coupling. A Butler matrix and a six-port junction with bandpass response are then developed based on the proposed rat-race coupler. They represent excellent candidates for miniaturised transceiver and direct conversion systems. The measured results are in good agreement with the simulated predictions.

General synthesis techniques for coupled resonator networks

This article presented general techniques for the synthesis and design of coupled resonator filters. The synthesis of the prototype circuit focuses on the compatibility between the coupling topology and the filtering function to be realized, providing some guidelines to select a proper coupling topology and to solve the coupling matrix synthesis problem. The dimensioning of the distributed filter is centered on parameter extraction techniques.

New method for wideband excitation of interdigital surface-wave transducers

A new method of designing coupled resonator networks for wideband excitation of interdigital surface-wave transducers is described. The elements of the tuning network are chosen, using an optimisation computer program. The insertion loss is minimised over the bandwidth of interest. For interdigital transducers on a monolithic zinc-oxide-on-silicon structure with Δv/v = 0.0036, a fractional bandwidth of 20% can be obtained. For a narrow-acoustic-beam interdigital transducer on a LiNbO3 halfspace with Δv/v = 0.022, a fractional bandwidth of 40% can be obtained. The design of the coupled resonator network takes into consideration the variation of the transducer acoustic impedance with frequency.