Defected Ground Slot Research Articles

A new insightful exploration into a low profile ultra-wide-band (UWB) microstrip antenna for DS-UWB applications

Designing a simple and planar antenna for high speed short distance ultra-wideband (UWB) communication has become a buzzword over the last few years. There are two very different categories of UWB technologies of vital relevance, i.e. (i) carrier-free direct sequence UWB (DS-UWB), and (ii) the Multi-Band orthogonal frequency division multiplexing UWB (OFDM UWB) technology. In, Multi-Band OFDM UWB technology, multi narrowband UWB antennas with frequency notches are required. However, in DS-UWB technology, the frequency spectrum of very short duration transmitted pulses occupies wide bandwidth, and hence to transmit it, the antenna should be fully matched over the entire bandwidth without the presence of any frequency notch. In this paper, a novel, small and completely planar air gap and defected ground slot integrated rectangular microstrip antenna with dual shorting posts have been thoroughly investigated to yield UWB, i.e. (109%) bandwidth without the presence of any frequency notch.

Wideband Compact Triangle-Slot Antenna With Out-of-Band Rejection

A wideband and compact triangle-slot antenna with out-of-band rejection is proposed. The antenna covers the whole C-band (4–8 GHz) including the 5.8 GHz ISM and sub-6 GHz band of 5G. First, a right-angled triangle-slot antenna is developed from a rotated square-slot antenna with a 50% size miniaturization. Then, a defected ground slot (DGS) and a thin microstrip line section are integrated into the antenna to improve the out-of-band rejection. This prevents the noise and unwanted interference to the receiver and effectively suppresses the high-order harmonics from the transmitter. Importantly, the added DGS and thin microstrip line increases the bandwidth up to 5.51 GHz (82.7% fractional bandwidth) and reduces the antenna size. Finally, by adding matching elements using stacked rectangular slot principle, the antenna size is reduced furthermore, leading to a total 60% reduction in size. The final ground size is 32 × 32 mm, which is suitable to be integrated into portable devices. The return loss is measured up to the third harmonic of the highest working frequency and compared with the reference triangle-slot antenna to validate the rejection concept. The out-of-band return loss remains smaller than 1.2 dB up to 26.5 GHz. The maximum improvement of return loss is 33.3 dB at 26.4 GHz, from 34.4 dB of the reference antenna to 1.1 dB of the proposed antenna.

An Eight-Element Frequency Reconfigurable MIMO Slot Antenna with Multi-band Tuning Characteristics

In this work, a novel rectangular slot-based MIMO frequency reconfigurable antenna design is presented for cognitive radio (CR) front-end applications. This antenna design consists of eight rectangular-shaped antenna elements etched on ground plane. The proposed design provides multi-band operation by employing a meandered type slot in center of every antenna. It provides a frequency tunable band between 1.6 and 2.48 GHz as well as two more bands on 3.6 GHz and 5.2 GHz, hence covering various wireless standards like GSM, UMTS, LTE, WiMAX, Bluetooth and WiFi. Varactor diodes are employed in the center of each element to get frequency reconfigurability by changing the capacitive reactance of the slot. Furthermore, rectangular defected ground slots are utilized between vertically positioned antenna elements for isolation improvement. The complete design is realized on FR-4 substrate of size 120 × 60 × 0.8 mm3. The simulation and measurement results exhibit good agreement. The design is simple, low-profile, compact and planar in structure making it suitable for CR applications.

Defected Ground Plane of Wearable Circular Patch Antenna

In this paper, Circular patch antenna design with defected ground plane is designed. The antenna is designed with circular patch and defected ground plane to allow it to operate in lower frequency as well as improved the antenna gain. The antenna has a feeding port and two defected ground slots to affect the frequency of the antenna. The proposed antenna is designed and simulated using Computer Simulation Technology (CST) Studio Suite 2016. The designed antenna has an operating frequency of 2.42GHz. A prototype has been fabricated and tested using network analyser and the measured results are in a good agreement with simulations.

Study of multiple antennas with defected ground slot for low-band LTE application

This study is focused on highly coupled multiple antennas with defected ground slot techniques. Two Printed Inverted-F Antenna (PIFA) are positioned at the top edge of chassis symmetrically. Both antennas are operating at low-band Long-Term Evolution (LTE) with center frequency, 829MHz. Rectangular defected ground slot is implemented to reduce the coupling effect between the antennas on the ground plane of the small chassis. Parameter study of the rectangular defected ground slot is studied with different width, W and length, L. Furthermore, the optimized dimensions of rectangular defected ground slot, W and L are simulated and presented. The optimized defected ground slot reduced the mutual coupling up to -4.5 dB. The envelope correlation coefficient (ECC) achieved less than 0.5. The ground plane of the multiple antenna structure has been further investigated by introducing another slot with a gap of 1mm between them. The achieved result is not significant in term of S-parameter and ECC compared to single defected ground slot.

Study of multiple antennas with defected ground slot for low-band LTE application

This study is focused on highly coupled multiple antennas with defected ground slot techniques. Two Printed Inverted-F Antenna (PIFA) are positioned at the top edge of chassis symmetrically. Both antennas are operating at low-band Long-Term Evolution (LTE) with center frequency, 829MHz. Rectangular defected ground slot is implemented to reduce the coupling effect between the antennas on the ground plane of the small chassis. Parameter study of the rectangular defected ground slot is studied with different width, W and length, L. Furthermore, the optimized dimensions of rectangular defected ground slot, W and L are simulated and presented. The optimized defected ground slot reduced the mutual coupling up to -4.5 dB. The envelope correlation coefficient (ECC) achieved less than 0.5. The ground plane of the multiple antenna structure has been further investigated by introducing another slot with a gap of 1mm between them. The achieved result is not significant in term of S-parameter and ECC compared to single defected ground slot.

Ultracompact CMOS 60-GHz Tapped-Line Combline BPF With Two Transmission Zeros Using Defected Ground Structures

In this paper, we propose a compact on-chip 60-GHz bandpass filter (BPF) in complementary metal–oxide–semiconductor (CMOS) technology. The CMOS BPF employs a tapped-line combline configuration with folding and overlapping to achieve a compact size. The combline BPF is realizable with low insertion loss (IL) due to capacitive loading, which reduces the physical length of the resonators and consequently reduces the resulting attenuation. Finally, defected ground slots are implemented in the ground plane under the coupled arms for additional performance enhancement and to achieve more size compactness. The measured IL and return loss of the fabricated prototype BPF are 3.2 and 31 dB, respectively, at a center frequency of 59 GHz with 14 GHz of bandwidth. The core chip area is 0.0165 mm2 ( $0.002\times \lambda _{g}^{2}$ ), which is the smallest BPF so far in the used technology.

A Miniaturized and High Gain Double-Slot Vivaldi Antenna Using Wideband Index-Near-Zero Metasurface

In this paper, a wideband, miniaturized, and high gain double-slot Vivaldi antenna is proposed. First, a corner cutting technique is adopted to broaden the frequency band. Second, a pair of defected ground slots is added to the edges of the antenna to extend the low-end frequency limitation from 2.27 to 1.15 GHz, which provides a great design freedom. Third, a novel unit cell of an index-near-zero metasurface is proposed in our design. The unit cell is a two-stub-loaded split-ring resonator, which has a compact size, a wide frequency band, and a good reflection coefficient. The gain of the double-slot Vivaldi antenna is improved over a wide frequency band by the inclusion of the index-near-zero metasurface in the aperture, without changing the overall dimensions or compromising the whole frequency band performance of the antenna. Finally, to verify the design method, an ultra-wideband double-slot Vivaldi antenna with defected ground slots and metasurface was fabricated and measured. The circuit has an overall size of $0.76\,\,\lambda \text{g}\,\,\times0.41\,\,\lambda \text{g}\,\,\times 0.005\,\,\lambda \text{g}$ . The modified antenna exhibits a measured gain of 0.7–14 dBi over the frequency band of 1.13–12 GHz.

Sierpinski fractal antenna for internet of things applications

Internet of Things is a new classification of Internet application which makes the information be common on a global scale. A major requirement for sharing is the transmitting and receiving of data or information which is done by antennas. Since large data on multiple frequencies needs to be shared, multiband antenna is a major requirement. In a multiband antennas design, different bands are active for different frequency ranges and bands. This property can be fulfilled by adding slots in patch, defected ground slot and by fractal in antennas. In the proposed paper fractal design is used because of its advantages like compact size, wideband, frequency independent, and low mutual coupling. A coaxial fed antenna formed by a right-angled isosceles triangular with Sierpinski structure is presented. The antenna covers all the bands i.e. WLAN/GSM/LTE/WiMAX/UWB. It is suitable for internet of things devices with its multiband characters. The analysis is also done with different iterations, substrate materials and thickness. Parameters like return loss, gain, bandwidth and directivity of proposed structures are studied and analyzed. CST Microwave studio tool is used for simulation results.

A Novel Wideband Microstrip Line to Ridge Gap Waveguide Transition Using Defected Ground Slot

In this letter design of a novel, wideband and low loss microstrip line transition to ridge gap waveguide is described. The transition is made up of two sections. The first section is a microstrip line that feeds a slot on the ground plane. The microstrip line is placed inside a metal box. The second part is the slot to ridge gap waveguide matching section. The proposed design has a broadband coupling to ridge gap waveguide and covers the whole stop-band of the periodic gap structure. The design optimization is performed for the microstrip line, slot size and ridge gap waveguide matching ridges. A prototype in Ku-band is manufactured and measured that shows a return loss less than 14 dB and a back-to-back insertion loss smaller than 0.5 dB for the given bandwidth. The microstrip transition enables integration of monolithic microwave integrated circuits (MMICs) in ridge gap waveguide technology.