Experimental Demonstration of Sixth Order Degenerate Band Edge in Coupled Microstrip Waveguides

Frozen Mode in Three-Way Periodic Microstrip Coupled Waveguide

We demonstrate theoretically and experimentally that a periodic three-way microstrip coupled waveguide exhibits a stationary inflection point (SIP). The SIP is a third order exceptional point of degeneracy (EPD) where three eigenmodes of the guiding system coalesce to form a stationary frozen mode with zero group velocity. Here the frozen mode is shown in a reciprocal waveguide; therefore three coupled waveguides (called three-way waveguide) are required, supporting three modes in each direction. We illustrate the occurrence of the frozen mode regime by observing the dispersion diagram and by …

倒置微带间隙波导共面EBG滤波器用于天线应用

Inverted Microstrip Gap Waveguide Coplanar EBG Filter for Antenna Applications

本研究提出倒置微带间隙波导共面EBG滤波器，通过蘑菇型元件实现紧凑阻带，X波段5单元滤波器达到-35.4 dB抑制和低损耗，适用于天线馈电网络集成。

A Topological Directional Coupler Fed by Microstrip Line with Configurable Coupling Coefficient

Topological waveguides have been extensively studied for their robust transmission properties immune to defects and their application potentials for microwave and terahertz integrated circuits. In this work, by using grounded planar valley-Hall photonic topological insulators, a high-efficiency topological directional coupler fed directly by microstrip line with configurable coupling coefficient is theoretically proposed and experimentally demonstrated. The topological directional coupler consists of two coupled topological waveguides, which can be directly integrated with microstrip circuits.…

Pulse Generation Based on a Microstrip Circuit with Fourth Order Degenerate Band Edge

A pulse generation scheme is proposed based on a structured resonance in a cavity where the non-conventional energy distribution is concentrated in its middle part. The cavity is first used as an oscillator during the energy charging step and when a switch is activated the signal is extracted from its center. The key component of the proposed scheme is the periodic microstrip waveguide with a fourth-order degenerate band edge (DBE) of its wavenumber-frequency dispersion diagram. The DBE is an exceptional point degeneracy condition that is responsible for the energy to be localized at the cavit…

Mid-infrared quantum cascade laser frequency combs with a microstrip-like line waveguide geometry

In this work, a design for a mid-infrared quantum cascade laser (QCL) frequency comb source that enhances the high frequency response and the comb characteristics of the device is presented . A state-of-the-art active region (AR), grown on a heavily n-doped InP:Si substrate, was processed into a buried heterostructure with a microstrip-like line waveguide. As a result, the repetition rate frequency $f_{rep}$, around 11.09 GHz, can be locked to an injected narrow-linewidth radio frequency (RF) signal, over a range of more than 200 kHz with -10 dBm of injected power, which outperforms normal bur…

Experimental Demonstration of a New Oscillator Concept Based on Degenerate Band Edge in Microstrip Circuit

The first experimental demonstration of an oscillator based on a periodic, resonant microstrip circuit with a degenerate band edge (DBE) is presented. The DBE is a fourth-order exceptional degeneracy of the eigenmodes in a lossless periodic waveguide that is visible in the wavenumber-frequency dispersion diagram, and the periodic microstrip behaves as a frequency selective medium. The presence of the DBE condition and the associated DBE resonance allow for a stable, single-mode oscillation as well as stability with varying the load resistance.