Hairpin Resonator Research Articles

A Balanced Feed Filtering Antenna With Novel Coupling Structure for Low-Sidelobe Radar Applications

A fourth-order filtering patch antenna with a novel coupling structure is presented in this paper. Using the proposed coupling structure, both the balanced coupling feed and cross-coupling are realized. Two identical slots etched on the ground plane are utilized to excite the radiating patch with the reduced cross-polarization level. A short slot etched on the ground plane is employed for cross-coupling, which introduces two controllable radiation nulls with a steep roll-off rate. In addition, owing to the split-ring resonators and hairpin resonators, the improved impedance bandwidth is achieved with the fourth-order filtering response. To demonstrate the proposed design techniques, both the filtering antenna element and the low-sidelobe array are designed, fabricated, and measured. The measured results show that the proposed antenna has the impedance bandwidth of 12% (4.78–5.39 GHz) with the total height of $0.06\lambda _{0}$ , the cross-polarization level lower than −31 dB, and two radiation nulls with the suppression higher than 31 dB. For the low-sidelobe antenna array, wide impedance bandwidth is also obtained with the sidelobe level below −28.7 dB, the cross-polarization level below −34 dB, and the out-of-band suppression better than 25 dB.

An Accurate Filtenna Synthesis Approach Based on Load-Resistance Flattening and Impedance-Transforming Tapped-Feed Techniques

In this paper, an accurate filtenna synthesis approach is investigated and verified for achieving the expected filtering response. The load-resistance flattening technique is carried out by attaching the shunt inductive/capacitive elements to cancel the unwanted parasitic element in the antenna model. The synthesis procedure was presented for a filtenna using a planar inverted-F antenna based on parallel-coupled lines. Furthermore, to economize the circuit area, hairpin resonators are adopted to replace the straight resonators in the PCL filtenna, and a tapped-feed structure is utilized for feeding. Thorough investigation reveals that conventional tapped-line feeds based on a singly loaded resonator adopted in a generic coupled-resonator filter requires careful modification to retrieve zero-reactance at the operation frequency. For verification, two bandpass filters were designed with hairpin uniform-impedance and stepped-impedance resonators, thereby validating the practicality of the proposed impedance-transforming tapped feeds. Eventually, the load-resistance flattening and impedance-transforming tapped-feed techniques are combined for developing an accurate filtenna synthesis approach. Two filtennas taking advantage of inverted-L and slotline antennas were designed and fabricated, thus, validating the feasibility of the proposed approach.

Unloaded Quality Factor for Hairpin Resonator Affected by Conduction and Radiation Losses on K-band

Unloaded Quality Factor for Hairpin Resonator Affected by Conduction and Radiation Losses on K-band

Integrated Dual-Band Filtering/Duplexing Antennas

In this paper, the state-of-the-art integrated filtering antennas with dual-band operation are first reviewed. Then, two designs of dual-band microstrip filtering antennas with a low-frequency ratio are presented. The 1st design is a dual-band dual-polarization (DBDP) antenna with a frequency ratio of 1.2 on a single patch, by employing the coupled resonator technique. Two bands at each polarization are achieved by vertically coupling a hairpin resonator with a patch through a slot in the ground plane and then coupled to a dual-mode stub loaded resonator. Each band exhibits a 2nd-order filtering performance with improved bandwidth and out-of-band rejection. Such an integration technique could significantly reduce the dimension and the complexity of the traditional DBDP antennas/arrays. In the 2nd design, a novel dual-port dual-band antenna (with a frequency ratio of 1.38) with the integrated filtering and duplexing functions is proposed. The frequency duplexing function is implemented by coupling a single patch with two sets of resonator-based filtering channels via a U-slot resonator inserted in the ground. This device seamlessly integrates the functions of duplexers, filters, and antennas in a very compact structure.

Improved Hairpin Resonator for Microfluidic Sensing

Improved Hairpin Resonator for Microfluidic Sensing

Design and fabrication of a compact microstrip low-pass filter with ultra-wide stopband and sharp roll-off-rate

Microstrip low-pass filters (LPFs) with good performance are used in most telecommunication systems. In this study, a modified T-shaped hairpin resonator is used to design LPF, and suppression cells are used to improve the performance of the filter in the stopband up to 22 GHz. The proposed LPF had a -3 dB cut-off frequency of 1.89 GHz. The proposed LPF is designed, fabricated and measured. The simulated and measured results for the proposed LPF are in good agreement with each other. Attenuation in the stopband is 34 dB, which is an extremely large number. Roll-off-rate (ROF or ζ) parameter is sharp and equal to 96.3 dB/GHz. The group delay in the passband is almost constant and in the range of 0.3-0.42 ns. In the following, an SMV-1247-079LF SMD varactor diode is used to adjust the proposed LPF. The tuning range for the proposed LPF is 0.46-3.2 GHz..

A new filter antenna using improved stepped impedance hairpin resonator

AbstractIn this letter, a filter antenna based on novel wide stop‐band low‐pass filter has been presented. The introduction of mushroom cell makes smaller structure and wider stop‐band of the antenna. The filter antenna works in the frequency from 1.8 to 2 GHz (10.5%), and exhibits a good out‐band rejection characteristic that the maximum frequency of the stop band is 13 GHz, which is 6.8 times of the central frequency. The measured results show a good agreement with simulated results.

Electron neutral collision frequency measurement with the hairpin resonator probe

Electron neutral collision frequency is measured using both grounded and floating hairpin resonator probes in a 27 MHz parallel plate capacitively coupled plasma. Operating conditions are 0.1–2 Torr (13.3–267 Pa) in Ar, He, and Ar–He gas mixtures. The method treats the hairpin probe as a two wire transmission line immersed in a dielectric medium. Measurements are obtained using a pressure and sheath correction process by sweeping over assumed collision frequencies in order to obtain the measured collision frequency. Results are compared to hybrid plasma equipment module simulations and show good agreement.

High-Selectivity single- and dual-resonator microstrip filters

New selective properties are revealed of the base section of conventional microstrip filters with circuits based on a four-wire system of coupled quarter-wave lines with one half-wave hairpin resonator. The conditions under which this single-resonator section acquires the characteristics of multi-resonator circuits due to the possibility of formation of four zeros and six operating attenuation poles at the end frequencies are determined. The structure does not contain elements short-circuited to the screen, which determines its high manufacturability. It is demonstrated that high-selectivity compact microstrip filters can be designed on the basis of single- and dual-resonator structures, i.e., the structures with the minimum number of resonators.

Erratum for: Miniaturized lowpass filter with wide band rejection using modified stepped‐impedance hairpin resonator

Erratum for: Miniaturized lowpass filter with wide band rejection using modified stepped‐impedance hairpin resonator

Miniaturized lowpass filter with wide band rejection using modified stepped-impedance hairpin resonator

Miniaturized lowpass filter with wide band rejection using modified stepped-impedance hairpin resonator

Design of Compact HTS Dual-Band Bandpass Filters Using Dual-Function Feeding Structure With Wide Stop-Band Response

We have developed a compact high-temperature superconducting four-pole dual-band bandpass filter (DBPF) using a dual-function feeding structure with a wide stop-band response. Use of shorted stub-loaded hairpin resonators enabled its achievement. The coupling coefficients are flexibly controlled by using a pair of H-shaped coupling elements between the resonators. A dual-function feeding structure is newly developed for flexibly adjusting the external coupling for the two bands. A tapped-line coupling is used to adjust the external coupling for the first band, and a coupled-line coupling is used to adjust the external coupling for the second one. The DBPF was designed to operate at 0.8 GHz with a 16-MHz (2%) bandwidth for the first band and at 2.0 GHz with a 40-MHz (2%) bandwidth for the second band. A compact (30 mm × 28.25 mm) filter was fabricated using YBa <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</sub> thin film on a CeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -buffered Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> substrate. The measured results agree well with the simulated ones.

A new miniature microstrip two-layer bandpass filter using aperturecoupled hairpin resonators

A new miniature microstrip two-layer bandpass filter using aperturecoupled hairpin resonators

Graphene‐metal based tunable band‐pass filters in the terahertz band

The authors propose the concept, analysis, and design of frequency tunable band-pass filters operating in the terahertz band. The proposed structure is composed of two metal tapped line and five metal-contacted graphene hairpin resonators transferred onto a dielectric. This structure implements low insertion loss and frequency tunability by adequately controlling DC bias applied on the graphene. An efficient synthesis method has been presented, through combining classical microwave filter theory and the electrical properties of graphene. The theoretical and extracted resonance frequency of resonator (f 0), external quality factor (Q E) and coupling coefficient (Kij ) are utilised to determine the filter circuit dimensions. Then the authors proposed two examples with different operating bandwidths to validate the theoretical design. The potentially high losses of graphene is also evaluated.

Miniaturized Dual-Band Bandstop Filter Using Multilayered E-Shape Microstrip Structure

This paperpresents a new design technique to realize a miniaturized dual-band rejection filter based on the E-shape microstrip structure for multifunctional wireless communication systems. The filter is designed on a double layer substrate to achieve compact size. On the bottom layer, two E-shape microstrip structures are realized and coupled through a space gap,gc, to perform the specified dual-bandstop response. The filtering response of the two bandstops is improved using a top layer substrate employing a main linestub. The main line is a half wavelength hairpin resonator. These two filter circuits are capacitivley coupled using overlapping microstrip lines.To demonstrate the proposed design technique, a multi-band bandstop filter is developed with rejection frequenciesof 2.4 and 5.3 GHz Wireless local Area Network (WLAN). The filter is designed and simulated using the momentum simulator of theAdvanced Design System (ADS) software package. The resulting filter has two second-order bandstops with four transmission poles and provides two band rejectionsof 25 dB and 35 dB at 2.4 GHz and 5.3 GHz respectively. The filter circuit size is very small, being of the order of about 26 mm2 excluding the feeding ports.

주파수 잠금회로를 이용한 발진기의 위상잡음 개선

본 논문에서는 주파수 잠금회로(FLL: Frequency Locked Loop)를 이용하여 발진기의 위상잡음을 개선할 수 있음을 보였다. 1차적으로 헤어-핀 공진기를 이용하여 전압제어발진기(VCO)를 제작하였다. 제작된 VCO는 발진주파수 5 GHz에서 위상잡음을 측정한 결과, 1 kHz offset 주파수에서 -53.1 dBc/Hz를 보였다. 위상잡음을 개선하기 위하여, VCO에 5 GHz 공진기로 구성된 주파수 검출기(frequency detector), 루프 필터, 전위변환기(level shifter)를 이용 궤환회로를 구성, 주파수 잠금회로를 구성하였다. 제작된 주파수 잠금회로는 5 GHz의 주파수에서 발진하고, 1 kHz offset 주파수에서 -120.6 dBc/Hz의 위상잡음을 보였다. 따라서 주파수 잠금회로를 이용, VCO의 위상잡음을 획기적으로 약 67.5 dB 개선할 수 있음을 보였다. 또한, 얻어진 주파수 잠금회로를 이용한 발진기의 위상잡음 성능은 수정발진기의 위상잡음과 비견할만한 것이다. In this paper, we showed the phase noise of voltage controlled oscillator(VCO) can be radically improved using FLL(Frequency Locked Loop). At first, a 5 GHz VCO is fabricated using a hair-pin resonator. The fabricated VCO shows a phase noise of -53.1 dBc/Hz at 1 kHz frequency offset. In order to improve the phase noise of the fabricated VCO, a FLL is constructed using the feedback loop that consists of the VCO, a frequency detector composed of 5 GHz resonator, loop-filter, and level shifter. The fabricated FLL is designed to oscillate at a frequency of 5 GHz, and its measured phase noise is about -120.6 dBc/Hz at 1 kHz offset frequency. As a result, the phase noise of VCO can be radically improved by about 67.5 dB applying FLL. In addition, the measured phase noise performance is close to that of crystal oscillator.

Compact Highly Integrated Planar Duplex Antenna for Wireless Communications

This paper proposes a novel concept of an integrated duplex antenna for realizing a compact multifunction RF front end by integrating a duplexer and a dual-band patch antenna. First, an all-resonator-based duplexer is designed. It is composed of two sets of split-ring resonators as channel filters, which are joined by a dual-mode stub-loaded resonator as the junction resonator. Then, a novel dual-band patch antenna is achieved by coupling a patch with a hairpin resonator through a slot in the ground. Uniform radiation characteristics have been achieved across the two bands. Finally, the duplexer is integrated with the dual-band patch antenna to form a highly integrated duplex antenna by coupling the hairpin resonator to the junction resonator of the duplexer directly. In this process, the 50- $\Omega $ interface and matching network between them are removed, contributing to a compact footprint. The details of codesign approach have been discussed in this paper. Compared with the traditional cascaded duplexer and antennas, this paper is much more compact and integrated but with an improved frequency response. A prototype of an integrated duplex antenna at S-band is fabricated and measured, showing two operation channels of 2.52–2.65 GHz for transmitting and 2.82–2.94 GHz for receiving with an isolation of over 32 dB. The measured results agree well with the simulation results.

Design of high–order HTS dual–band bandpass filters with receiver subsystem for future mobile communication systems

We have developed two high-order high-temperature superconducting (HTS) dual-band bandpass filters (BPFs) with a receiver subsystem for future mobile communication systems. They feature stub-loaded hair-pin resonators with two types of microstrip lines between them. One has a six-pole design, and the other has an eight-pole design. Both were designed to operate at 2.15GHz with a 43-MHz (2%) bandwidth for the lower passband and at 3.50GHz with a 70-MHz (2%) bandwidth for the upper one. They were fabricated using YBa2Cu3Oy thin film on a CeO2-bufferd r-Al2O3 substrate. The measured results for both filters agree well with the simulated ones. The HTS dual-band BPF receiver subsystem uses a pulse tube cryocooler and a wideband low noise amplifier (LNA). We measured the frequency response of the six-pole dual-band BPF with and without a wideband LNA with a gain of 10dB. The measured return losses were close.

Compact single‐layer depolarizing chipless RFID tag

ABSTRACTWe present the first single layer depolarizing chipless RFID tag. The tag is formed by a set of asymmetric hairpin resonators, improving the tag's coding density when compared with previous depolarizing tags. The single layer characteristics of the tags make it possible to print them directly on items or embed them in low profile objects like documents. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1897–1900, 2016

Compact microstrip lowpass filter with ultra-sharp roll-off and ultra-wide stopband using stepped impedance Hairpin resonator

A novel microstrip lowpass filter (LPF) with very sharp roll-off, compact size and ultra-wide stopband is presented in this paper. The structure consists of modified stepped impedance Hairpin resonator and a circular patch as a suppressor. The proposed LPF has the cut-off frequency of 1.07GHz. The simulation results indicated that the transition-band of the proposed LPF is 0.09GHz from −3 to −20dB. Maximum insertion-loss at about 80% of the passband is 0.1dB. The proposed LPF has been designed, fabricated and measured. From the measurements, good agreements with the simulated results are obtained. Also, an ultra-wide stopband was achieved. Proposed LPF has an ultra high figure-of-merit (FOM) of 151,523, which shows its strong efficiency.