Geonho Jang

A Novel Compact Metamaterial Zeroth Order Resonant Bandpass Filter for a VHF Band and Its Stopband Improvement by Transmission Zeros

A novel compact and low-loss VHF bandpass filter is presented with enhanced stopband performance using metamaterial zeroth order resonator (ZOR) characteristics. An in-line ZOR filter is initially suggested and changed to have transmission zeros (TZs) due to source-load coupling for effective improvement of the isolation from UHF wireless channels. The proposed filter is smaller than 1/10 of the conventional filters in terms of size and has relatively very low insertion loss (< 1 dB for the electromagnetic (EM) simulation and < 3 dB for the measurement) and return loss (<-20 dB) in the passband due to the approximately 80% size reduction and the higher isolation in the stopband due to the TZs. The circuit and EM simulation are in good agreement with the measurements.

Design of dualband metamaterial bandpass filter using zeroth order resonance

This paper proposes the design method based on the composite right/left-handed (CRLH) structure to miniaturize and generate the dual-band characteristic. For realization, we used the zero-th order resonance point of the CRLH and the simple theory of Inverter. The proposed technique is validated by the performance predictions and experiments, and it is found out that the suggested method enables the huge size reduction from the conventional filters such as the parallel coupled type which was designed following the half-wavelength resonance.

Compact Quad-Mode Bandpass Filter Using Modified Coaxial Cavity Resonator With Improved

This paper presents a novel quadruple-mode coaxial cavity resonator and its application to bandpass filters with compact size and improved quality factor (Q-factor). Unlike the conventional coaxial cavity resonator, the proposed resonator is made up of four inner conductive posts within a single cavity, which provides new quadruple resonant modes to realize bandpass filter. No metallic walls inside the cavity are required, and thus the utilization efficiency of the cavity space is improved. As a result, the unloaded Q can be approximately 15% higher in comparison to the conventional coaxial resonator, or 30%-35% volume saving can be achieved while maintaining the similar Q-factor value with the conventional designs. In addition, due to the multiple cross-coupling occurring within the cavity, including the source-to-load direct coupling, four flexible transmission zeros can be created to realize different filtering functions. The complete design methodology of filters based on the proposed resonator is discussed, starting with the resonator characteristics and the coupling scheme. Simulations as well as experimental results of four- and eight-pole filters are presented to validate this attractive design concept. Good agreement between measured and computed results is obtained.

Q

In this paper, a novel rectangular patch antenna is proposed to have Zeroth Order Resonance(ZOR) generated based on the Metamaterial Complosite Right- and Left-Handed(CRLH) structure. Making the in-phase electric field over the entire antenna other than a half-wavelength as the fundamental resonance mode of a standard microstrip patch or its positive multiple, the metallic patch is suggested to be capacitively coupled with only one surrounding rectangular ring, different from the previous 1D ZOR antennas commonly having several metal cells in line. The performance of the proposed antenna is simulated by a 3D field solver that inputs the sizes of the physical structure corresponding to the equivalent circuit designed to have ZOR at 2.4 GHz. Consequently, the resonance frequency, the gain and the antenna efficiency are observed 2.4 GHz, 5 dB and 98%, respectively. Besides, the important property of the proposed antenna is addressed as the combination of the low profile as an advantage of microstrip patch antennas, and the omni-directional field pattern typical of monopole antennas.

-Factor

In this paper, a novel circular patch antenna is proposed to have Zeroth Order Resonance(ZOR) generated based on the Metamaterial Composite Right- and Left-Handed(CRLH) structure. Making the in-phase electric field over the entire antenna other than a half-wavelength as the fundamental resonance mode of a ordinary microstrip patch or its positive multiple, the metallic patch is suggested to be capacitively coupled with only one surrounding circular ring, different from the previous 1D ZOR antennas commonly having several metal cells in line. The performance of the proposed antenna is simulated by a 3D field solver that inputs the sizes of the physical structure corresponding to the equivalent circuit designed to have ZOR at 2.4 GHz. Consequently, the resonance frequency, the gain and the antenna efficiency are observed 2.4 GHz, 5 dB and 98%, respectively. Besides, the important property of the proposed antenna is addressed as the combination of the low-cost low-profile as an advantage of microstrip patch antennas, and the omni-directional field pattern typical of monopole antennas.

A novel metamaterial CRLH ZOR microstrip patch antenna capacitively coupled to a rectangular ring

In this paper, the design of a new bandpass filter based on the modified circular mushroom metamaterial structure is proposed. In detail, half circular mushroom cells are used as the zeroth order resonators(ZOR), and an intermediate gap is adopted to introduce the coupling between neighboring ZOR resonators. The proposed bandpass filter design is validated by the circuit and 3D EM simulations and measurements compared to the target specifications, and the metamaterial properties are proved by the ZOR field distributions and dispersion diagram. Also, the effect of size reduction is addressed.

A novel metamaterial CRLH ZOR circular patch antenna capacitively coupled to a circular ring

In this paper, a novel rectangular patch antenna is proposed to have Zeroth Order Resonance(ZOR) generated based on the Metamaterial Complosite Right- and Left-Handed(CRLH) structure. Making the in-phase electric field over the entire antenna other than a half-wavelength as the fundamental resonance mode of a standard microstrip patch or its positive multiple, the metallic patch is suggested to be capacitively coupled with only one surrounding rectangular ring, different from the previous 1D ZOR antennas commonly having several metal cells in line. The performance of the proposed antenna is simulated by a 3D field solver that inputs the sizes of the physical structure corresponding to the equivalent circuit designed to have ZOR at 2.4 GHz. Consequently, the resonance frequency, the gain and the antenna efficiency are observed 2.4 GHz, 5 dB and 98%, respectively. Besides, the important property of the proposed antenna is addressed as the combination of the low profile as an advantage of microstrip patch antennas, and the omni-directional field pattern typical of monopole antennas.

Design of a Metamaterial Bandpass Filter Using ZOR of the Modified Circular Mushroom Structure

This paper discusses the resonant characteristics, such as the resonant frequencies and Q factors, as well as tuning methods of the resonant frequency of the triple-mode dielectric resonators, for their possible application to compact bandpass filters for mobile communication systems. The resonators include spheres and cylindrical rods that can be applied to compact bandpass filters. These high Q ceramic resonators can replace the conventional coaxial type resonators, which are large sized and also have relatively low Q values. Both simulated and measured results show that the Q values of the sphere and rod reach 27,000 and 24,000, respectively. Decoupling of degenerate modes is also briefly discussed.

Design of a Novel 2D-Metamaterial CRLH ZOR Antenna with a Microstrip Patch Capacitively Coupled to a Rectangular Ring

We propose a compact MIMO antenna with high inter-antenna isolation. It is featured by small radiating elements each of which comprises a meandered line and an open-loop, and a modified T-shaped decoupling structure to lower the interaction between the radiators. For a WiMAX band, the size of the entire MIMO antenna is 0.22λg showing effective miniaturization. And the gain, efficiency and isolation are 3.7dBi, 56% and 17dB, acceptable to the industrial standard.

Resonant Characteristics of Triple-Mode Dielectric Resonators

This paper presents the design of the compact UHF Bandpass filter of CT-type with a novel mixed coupling topology. In further detail, this new coupling structure mathematically equals the transmission zero that enables particularly the better rejection performance in the stopband without increasing the filters order. To envision this design concept, we fabricated a microstrip filter whose measurement proves to agree with the predicted performance and the suggested coupling structure reduces the overall size, and will be possibly used in the miniaturized UHF apparatus such as the RFID system.