Defected Ground Structure Pattern Research Articles

A Novel Design of Compact Dual-Band Bandpass Filter for Wireless Communication Systems

In this paper, design, fabrication, and measurement of a new microstrip dual-band bandpass filter with compact size and high selectivity characteristics for modern wireless communication systems is presented. The filter structure is composed of folded non-uniform meander resonators along with defected ground structure patterns. The proposed filter with a total size of 14.43 × 9.04 mm2 is designed to exhibit two passbands centered at 2.18 GHz and 5.12 GHz with fractional bandwidths of 16.2% and 6.48%, respectively. The measured insertion losses are about 1.13 dB and 2.65 dB at the lower and upper passband, respectively. The simulation and experimental measurement results are basically in good agreement which validate the proposed approach.

CPW based Band Pass Filter Using DGS for ISM Band Applications

The design and simulation of coplanar waveguide (CPW) bandpass filter (BPF) has been described in this paper. It mainly focuses on Defected Ground Structure (DGS), where U-shaped DGS with open stub in transmission line has been introduced. By etching the DGS pattern in ground and transmission will change the distribution of inductance and capacitance to produce filtering effect. This paper also discusses about the influence of geometrical parameter l for the improvement in the frequency response of bandpass filter. As increasing the dimension of the geometric parameter l shift the center frequency to the higher frequencies. This filter offers a bandwidth of 1.65 GHz with passband ranging from 2.1 GHz to 3.75 GHz with a stopband rejection is about -28 dB.

Ultracompact 60-GHz CMOS BPF Employing Broadside-Coupled Open-Loop Resonators

This letter presents a 60-GHz ultracompact on-chip bandpass filter (BPF). The designed filter is based on a unique structure, which consists of two overlapped broadside-coupled open-loop resonators, achieving a high level of miniaturization. Moreover, each resonator is loaded by a metal–insulator–metal capacitor to get further miniaturization. Defected ground structure pattern is constructed under the filter structure to enhance the insertion loss (IL). This BPF is designed and fabricated using a standard 0.18- $\mu \text{m}$ complementary metal–oxide–semiconductor technology for millimeter-wave applications. The fabricated BPF chip size is $240 \times 225~\mu \text{m}^{2}$ including pads. The measured results agree well with the simulation ones and show that the BPF has an IL of 3.3 dB at 59.5-GHz center frequency, and a bandwidth of 12.9 GHz.

A broad stopband common-mode suppression defected ground structure filter with complementary structure

A low-cost defected ground structure (DGS) wideband stopband filter adopting complementary structure is proposed, which is designed for common-mode noise suppression in high-speed differential signals. The filter is etched below the low cost FR4 printed circuit board. To avoid stimulating the common-mode noise, the DGS cells on ground planes are kept symmetrical to the central line of the two differential signal lines. Both sides of the filter adopt a symmetric cup-shape DGS structure and the middle of the filter adopts a symmetric umbrella-type structure. All of the DGS structures are complementary, which makes the filter compact and miniaturized. What is more, because the spaces among the three DGS are closer, there exist the mutual inductances among them, which are utilized to achieve a wide stopband filter. The simulated result demonstrates the proposed filter has a wideband bandwidth of 6.8 GHz over 20 dB. In order to analyze the effect of compact structure of the filter, a filter having the same DGS patterns but large spaces among them is compared with it. The simulated result demonstrates that the stopband bandwidth of the compared filter has a wideband bandwidth of 4.4 GHz over 20 dB, of which the bandwidth is about 2.4 GHz less than that of the proposed filter. It is obvious that there exists a mutual inductance in the compact DGS structure common-mode filter, which plays an important role in broadening the bandwidth of the proposed filter. In order to facilitate analysis, an equivalent model of LC circuit is also given. The equivalent parameters of LC can be deduced from the definition of 3 dB cut-off frequency and resonant frequency, of which the values can be obtained by the HFSS simulation. The simulated and measured results show that the differential signal under the DGS filter is nearly intact, and the common-mode noise can be reduced over 20 dB from 4.6 GHz to 11.4 GHz and over 15 dB from 4.3 GHz to 12 GHz, while the area of the filter is only 10 mm by 10 mm. Compared with the periodic DGS at the same suppression depth of common-mode noise over 20 dB, the method has the advantages that surface area is reduced to no more than 30%, and the stopband width is increased by over 50%.

결함접지구조와 가유전체 기판구조를 결합한 전송선로의 설계

본 논문에서는 결함접지구조와 가유전체 기판구조를 이용하여 새로운 초고주파 대역 전송선로 구조가 제안된다. 결함접지구조는 전송선로의 단위길이당 등가의 인덕턴스를 증가시켜 동일한 선폭일 때 전송선로의 특성 임피던스를 키우면서 선로의 길이를 줄여준다. 가유전체 기판구조는 전송선로의 단위길이당 등가의 커패시턴스를 증가시켜, 동일한 선폭일 때 전송선로의 특성 임피던스를 낮추면서 선로의 길이를 줄여준다. 따라서 결함접지구조와 가유전체 기판구조는 모두 전송선로의 길이를 줄이면서 선폭에 대해서는 상보적인 역할을 한다. 그러므로 두 구조가 결합되면 전송선로의 특성 임피던스는 크게 변하지 않은 채 길이만 더욱 줄일 수 있으므로, 초고주파 회로의 소형화에 크게 유리하다. 본 논문에서는 결함접지구조와 가유전체 기판구조를 모두 결합시킨 <TEX>$35{\sim}100{\Omega}$</TEX> 전송선로를 설계하고, 실제로 제작 및 측정하여 그 결과를 제시하는데, 특성 임피던스의 예측값과 측정값이 잘 일치함을 보인다. 동일한 전기적 길이에 대하여 제안한 전송선로는 Fig.준형 마이크로스트립 전송선로에 비하여 불과 55.4~76.9% 물리적 길이를 갖는다. In this work, a new high frequency transmission line structure combined with defected ground structure (DGS) and artificial dielectric substrate (ADS) structure is proposed. DGS patterns give add the additional inductance to transmission lines and results in the increased characteristic impedance for a given line width. To the contrary, ADS presents increased capacitance and reduced line impedance. So both play a role in reducing the length of transmission lines commonly, but in preserving the line impedance complementarily. This means that the length of transmission lines can be reduced furtherly by DGS and ADS without a critical change of line width compared to the cases when one of DGS and ADS is used only. As examples, <TEX>$35{\sim}100{\Omega}$</TEX> transmission lines having DGS and ADS are designed, fabricated, measured, and compared to the simulation results. A good agreement between the simulated and measured line impedances is presented. In addition, the physical lengths of the proposed transmission lines are only 55.4~76.9% of those of the normal microstrip lines for the same electrical lengths.

A Defected Ground Structure without Ground Contact Problem and Application to Branch Line Couplers

A new defected ground structure (DGS) microstrip line that is free from the ground contact problem is described together with its application example. The proposed DGS microstrip line adopts a double-layered substrate. The first layer contains the microstrip line and DGS patterns on the top and bottom planes as with the conventional DGS line. The second substrate, of which upper metal plane has already been removed, is attached to the bottom ground plane of the first layer. This structure prevents the ground plane of the first substrate with DGS patterns from making contact with the metal housing. The proposed DGS microstrip line has advantageous transmission and rejection characteristics, without the ground contact problem of DGS patterns, which has been a critical problem of previous DGS lines. A 10 dB branch line hybrid coupler is designed and measured, as an example of application of the proposed DGS microstrip line.

Design of compact low‐pass filter with large reject band using open circuit stubs and two‐cascaded DGS quasitriangular resonators

AbstractThis article investigates a quasitriangular of defected ground structure (DGS) for low‐pass filters (LPFs) application. An equivalent RLC circuit model is presented and its corresponding parameters are as well extracted using the parametric relationships. The LPFs using the proposed DGS pattern combined with open stubs are designed and fabricated. The proposed LPF presents the advantages of small size, low insertion loss and ultrawide stopband with 20 dB attenuation from 4 GHz to &gt;20 GHz. The simulated results obtained by equivalent circuit model and full‐wave electromagnet show good agreement with the measured ones. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:122–127, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27260

Comparative study of three shapes of DGS pattern and design of compact microstrip low-pass and band-pass filters

In this paper, three types of defected ground structure (DGS) units which are triangular-head (TH), rectangular-head (RH) and U-shape (US) are investigated and their characteristics are compared ea...

A Novel Compact Tunable Bandpass Filter Loaded Varactor Diode on the DGS

In this paper, a novel defected ground structure (DGS) pattern with enhanced effective capacitance (varactor diode) and a hole in PCB center is presented. The increase in effective capacitance enables the new DGS pattern to achieve a lower resonance than the DGS pattern for the same etched square dimension. The hole in the center also can make resonator frequency lower with better characteristic. According to the tunable characteristic of varactor diode, the resonant frequencies can be tunable. Simulation results show that a lower resonance is achieved with active device, compared to a common DGS pattern.

Improving performance of non-duplexer active transceiver antenna with defected structures

The implementation of an active transceiver patch antenna without duplexer is reported. The isolation of the transmitting-receiving ports is increased by almost 20 dB by using defected ground structure patterns obtaining more than 50 dB; besides, cross-polarisation levels are also decreased by more than 15 dB. On the other hand, the use of spur lines allows increasing the linearity of the transmitting path, obtaining a low-harmonic distortion class E power amplifier. In the receiving path, a high-linear low noise amplifier (LNA) is employed with a third-order input intercept point close to 20 dBm. Both amplifiers are built with heterounion bipolar transistor (HBT). To prove the idea, as an example, the operation frequencies and channel separation of the GSM1800 were taken into account for a practical design. The complete active antenna is developed with characteristic impedances different from 50 Ω to obtain optimal performance of the active blocks.

Quasi-elliptic filter characteristics of an asymmetric defected ground structure

An asymmetric defected ground structure (DGS) with respect to a microstrip line is proposed. Its unit cell consists of two square slots connected with a rectangular slot by meandered transverse slots. The simulated, measured and equivalent circuit responses have been presented. The unit DGS pattern under microstrip line produces wide rejection bandwidth and high sharpness factor. Its elliptic band-reject filter response is modelled by appropriate LC equivalent circuit. Two such DGS cells under a microstrip line produce 3-pole quasi-elliptic bandstop filter response, which shows deeper attenuation without appreciable change in pole frequencies in comparison to single cell structure. Unit DGS pattern under coupled gap microstrip lines produces band-accept filtering characteristics. The frequency characteristics show a quasi-elliptic highpass filtering characteristics with sharp lower transition knee. Accordingly, an LC equivalent circuit is proposed. A cascaded band-accept and band-reject filter is proposed for designing a wideband bandpass filter. The bandwidth and centre frequency of the bandpass filter can be varied by choosing different set of DGS dimensions.

이중 기판 결함 접지 구조를 이용한 비대칭 월킨슨 전력 분배기

종래의 DGS를 이용한 초고주파 회로의 메탈 패키징(metal packaging)시 존재했던 DGS의 접지면 접촉 문제를 해결하고자, 본 논문에서는 이중 기판 결함 접지 구조 구조를 제안하고, 이를 1:4 비대칭 전력 분배기에 적용한 응용예를 제시한다. 이중 기판에 구현된 사각형 DGS는 종래와 같이 마이크로스트립 선로의 특성 임피던스를 표준형 선로보다 크게 증가시킨다. 이중 기판 DGS 구조를 형성하기 위하여 제2유전체 기판이 DGS가 구현된 기판면의 바닥 접지면에 접합된다. 따라서 제2유전체 기판이 메탈 패키지 바닥면에 장착되므로, DGS가 직접 패키지 접촉되는 것을 막을 수 있다. 초고주파 회로 응용예를 보이기 위해, 이중 기판 DGS를 이용하여 패키지 접지 문제를 해결한 1:4 비대칭 전력 분배기의 설계 및 측정 결과가 제시되는데, 시뮬레이션과 측정 결과에 있어서 잘 일치하는 특성을 보인다. A novel 1:4 unequal wilkinson power divider using rectangular-shaped defected ground structure(DGS) in double layered substrate is proposed for removing the ground problem of DGS in packaging. Rectangular-shared DGS produces the transmission line having much higher characteristic impedance than standard microstrip line. The proposed unequal divider is composed of DGS and double layered substrate in order to be free from the ground problem of DGS patterns in packaging in metal housings. The second substrate is attached to the first substrate which contains DGS pattern on its ground plane at the bottom side to form the double layered substrate. In order to show the validity of the proposed DGS in the double layered substrate, a 1:4 unequal power divider is designed and measured. The predicted and measured performances are shown with an excellent agreement between them.

Small-Sized High-Power PIN Diode Switch with Defected Ground Structure for Wireless Broadband Internet

This letter presents a small-sized, high-power single-pole double-throw (SPDT) switch with defected ground structure (DGS) for wireless broadband Internet application. To reduce the circuit size by using a slow-wave characteristic, the DGS is used for the quarter-wave (λ/4) transmission line of the switch. To secure a high degree of isolation, the switch with DGS is composed of shunt-connected PIN diodes. It shows an insertion loss of 0.8 dB, an isolation of 50 dB or more, and power capability of at least 50 W at 2.3 GHz. The switch shows very similar performance to the conventional shunt-type switch, but the circuit size is reduced by about 50% simply with the use of DGS patterns.

DGS pattern with enhanced effective capacitance

A new defected ground structure (DGS) pattern with enhanced effective capacitance is presented. The increase in effective capacitance enables the new DGS pattern to achieve a lower resonance than the dumb-bell shaped DGS pattern for the same etched square area dimension. Simulation and experimental results show that a 1.32 GHz lower resonance is achieved with the new DGS pattern, compared to a dumb-bell shaped DGS pattern.

Microstrip Patch Antenna With Defected Ground Structure for Cross Polarization Suppression

A defected ground structure (DGS) is proposed to reduce the cross-polarized (XP) radiation of a microstrip patch antenna. The proposed DGS pattern is simple and easy to etch on a commercial microstrip substrate. This will only reduce the XP radiation field without affecting the dominant mode input impedance and co-polarized radiation patterns of a conventional antenna. The new concept has been examined and verified experimentally for a particular DGS pattern employing a circular patch as the radiator. Both simulation and experimental results are presented.

Design of lowpass filters using defected ground structure and compensated microstrip line

A method to design lowpass filters (LPF) using defected ground structure (DGS) and compensated microstrip line is presented. Using the extracted equivalent elements of DGS and capacitive microstrip line, an LPF having no open stub, high impedance line, and tee- or cross-junction element, is designed. Only two DGS patterns and one broad microstrip line comprise the LPF Simple structure, small size (half of a conventional LPF), less discontinuities, and high power handling capability are obtained through the proposed LPF.