Frequency Band-stop Performance Research Articles

Wearable Doppler Radar with Integrated Antenna for Patient Vital Sign Monitoring

ABSTRACTIn this article, a wearable Doppler radar unit with radio data link in 2.4 GHz for use in portable patient monitoring and emergency response is presented. By using a rotated E-shaped strip in the radiating patch, a new resonance at lower frequencies (2.4 GHz) can be achieved. Also, by embedding cutting a rectangular slot with protruded interdigital strip inside the slot in the feed line a frequency band-stop performance can be achieved. The proposed structure has a major advantage in high harmonic rejection. In order to generate efficient RF to dc conversion, we use a pair of gap distances in the microstrip loop. Unlike portable electrocardiograms (ECG) or photoplethysmography, the near-field Doppler unit enables monitoring of the person’s heart rate without the need for electrical contact or optical access to the patient’s skin. The Doppler unit is designed to be embedded in a clothing garment, such as a shirt or vest, or used by medical emergency personnel in an instrumented blanket or medical stretcher. Since the Doppler unit is placed directly on or behind the patient’s torso, the extraneous signals due to relative motion artifacts are greatly reduced. Low-cost design is achieved by employing pulse wideband microstrip elements for the integrated patch antenna, microwave oscillator, and tuning elements. Also, since the distance between the Doppler unit and the patient is fixed, it was possible to tune the detection phase to enable the use of a single mixer diode and eliminate the need for quadrature detection. This approach is demonstrated using a simple direct conversion radar circuit implemented in a microstrip operating at 2.460 GHz. Heart rate data is shown for detection distances of 0.5 meter. Measured heart data from this technique shows a clear waveform substructure similar to the Personal Questionnaire Rapid Scaling Technique complex features found in captured ECG data.

Bandwidth Enhancement of Small Slot Antenna with a Variable Band-Stop Function

In this paper, a novel and compact design of microstrip slot antenna with band-notched characteristic for UWB application is proposed. In the proposed design, an inverted T-shaped slot at the square radiating stub is used to create an additional resonance at the higher frequencies. By obtaining this resonance, the usable upper frequency of the antenna is extended from 10.3 to 17.6 GHz which provides more than 140 % fractional bandwidth. Additionally, by cutting a pair of step-shaped slits in the ground plane, a desired frequency band-stop performance has been obtained. Experimental results obtained for this antenna show that it exhibits good gain and radiation pattern characteristics within the UWB frequency range. The proposed antenna can operate from 2.9 to 17.1 GHz for VSWR <2 with a rejection band around of 5–6 GHz to suppress any interference from wireless local area network systems. Simulated and measured results are presented to validate the usefulness of the proposed antenna structure for UWB applications.

A Novel Design of Low Power Rectenna for Wireless Sensor and RFID Applications

In this paper, an efficient microstrip rectenna operating on ISM band with high harmonic rejection is presented. By using rotated E-shaped strip in the radiating patch, a new resonance at lower frequencies (2.4 GHz) can be achieved. Also by embedding cutting a rectangular slot with protruded interdigital strip inside the slot in the feed line a frequency band-stop performance can be achieved. The proposed structure has a major advantage in high harmonic rejection. The rectenna with integrated monopole antenna can eliminate the need for an low pass filter placed between the antenna and the diode as well as produce higher output power, with maximum conversion efficiency of 74 % using a 1 K $$\Omega $$ Ω load resistor at a power density of $$0.3\,\hbox {mW/cm}^{2}$$ 0.3 mW/cm 2 .

Microstrip monopole antenna with dual band-stop function for ultrawideband applications

In this study, a new design of dual band-notched monopole antenna for ultrawideband (UWB) systems has been presented. The antenna consists of a pair of rotated T-ring strips protruded inside square-ring radiating patch, a feed line, and a ground plane with a pair of rotated E-shaped slot, which provides a wide usable fractional bandwidth of more than 140% with double band-stop performance. By applying the pair of rotated E-shaped slots in the ground plane, a new resonance at higher frequency range (14 GHz) is excited and much wider impedance bandwidth can be produced. In the proposed monopole antenna, to generate a single and dual frequency band-stop performance, we convert the square radiating patch to the square-ring structure with protruded T-ring strips. Simulated and measured results obtained for this antenna show that the proposed antenna offers very wide bandwidth from 2.65 to 15.1 GHz with two notched bands covering all the 5.2/5.8 GHz WLAN, 3.5/5.5 GHz WiMAX, and 4 GHz C bands. Simulated and experimental results obtained for this antenna show that it exhibits good radiation behavior within the UWB frequency range. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:818–822, 2014

APPLICATION OF PROTRUDED STRIP RESONATORS TO DESIGN AN UWB SLOT ANTENNA WITH WLAN BAND-NOTCHED CHARACTERISTIC

In this paper, a difierent method for designing a novel and compact microstrip-fed slot antenna with band-notched characteristic for UWB application is proposed. In the proposed antenna, a pair of cross-shaped strips protruded inside an extra rectangular slot in the ground plane are used to crate an additional resonance in higher frequencies. By obtaining this resonance, the usable upper frequency of the antenna is extended from 9 to 14.8GHz which provides a wide usable fractional bandwidth of more than 135%. Additionally, by using a square ring radiating stub with a pair of protruded T-shaped strips inside the ring, a desired frequency band-stop performance has been obtained. Good antenna gain and VSWR characteristics are obtained in the frequency band of interest. The proposed antenna can operate from 3.04 to 14.8GHz for VSWR < 2 with a rejection band around 5.1 to 6GHz to suppress any interference from wireless local area network (WLAN) systems. Simulated and experimental results obtained for this antenna show that it exhibits good radiation behavior within the UWB frequency range.

DUAL BAND-NOTCHED MONOPOLE ANTENNA WITH MULTI-RESONANCE CHARACTERISTIC FOR UWB WIRELESS COMMUNICATIONS

In this manuscript, a novel design of ultra-wideband (UWB) monopole antenna with dual frequency band-stop performance is proposed. The proposed antenna consists of an ordinary square radiating patch with a pair of rotated T-shaped slits, and a modifled ground plane with an inverted ›-shaped and a pair of rectangular-ring slots. In the presented structure, by cutting a pair of rectangular- ring slots in the ground plane, additional resonances are excited and hence much wider impedance bandwidth can be produced, especially at the higher band that the antenna provides a wide usable fractional bandwidth of more than 140% (2.8{17.5GHz). In order to generate single band-notched characteristic, we cut a pair of rotated T-shaped slits in the square radiating patch. Finally, by inserting an inverted ›-shaped slot in the ground plane, a dual band-notched function is achieved. The measured results reveal that the presented dual band-notch monopole antenna ofiers a very wide bandwidth with two notched bands, covering all the 5.2/5.8GHz WLAN, 3.5/5.5GHz WiMAX and 4GHz C bands. The designed antenna has a small size of 12 £ 18mm 2 . Good return loss, antenna gain and radiation pattern characteristics are obtained in the frequency band of interest. Simulated and measured results are presented to validate the usefulness of the proposed antenna structure for UWB applications.

Dual band-notch square monopole antenna with a modified ground plane for UWB applications

This paper presents a novel small square monopole antenna for UWB applications with dual band-notch function. By cutting an S-shaped slot in the ground plane, additional resonance is excited and hence, much wider impedance bandwidth can be produced, especially at the higher band that provides a wide usable fractional bandwidth of more than 120% (2.98–12.25 GHz). To generate a single frequency band-stop performance, we add a pair of C-shaped parasitic structures in the ground plane, and also in order to create the second notch frequency, we insert a horizontal rectangular strip in the center of two C-shaped parasitic structure in the ground plane. The measured results reveal that the presented dual band-notch monopole antenna offers a wide bandwidth with two notched bands, covering all the 5.2/5.8 GHz wireless local area network, 3.5/5.5 GHz WiMAX, and 4 GHz C bands. Good and radiation behavior within the UWB frequency range have also been obtained. The antenna has a small dimension of 12 × 18 mm2. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2743–2747, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27209

A novel elliptic microstrip FED antenna with double band notched characteristic for UWB application

AbstractA compact ultrawideband microstrip‐fed monopole antenna with two band notch property is presented.The antenna consists of a truncated elliptic patch with half wave arc slot and two parasitic bent elements in both side of the radiating patch. It is designed with half elliptic ground plane in the back of the radiating patch. The antenna provides an enhanced impedance matching characteristic over the desired frequency band, with variable dimensions which are used to generate the frequency band stop performance in wireless local area network and the worldwide interoperability for microwave access frequency bands. The antenna is designed and measured successfully. The measured results show that this antenna operates over the frequency band between 2.2 and 11.5 GHz for S11 &lt; 10 dB, while showing the band rejection performances in the frequencies band of 3.2–3.8 GHz and 5.2–5.8 GHz. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2659–2662, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27130

Square Monopole Antenna for UWB Applications With Novel Rod-Shaped Parasitic Structures and Novel V-Shaped Slots in the Ground Plane

A novel band-notched ultrawideband monopole antenna is presented. The proposed antenna consists of a stepped square radiating patch, two rod-shaped parasitic structures for generating band-notched function instead of changing the patch or feeding shapes, and a notched ground plane with two novel V-shaped slots that provide a wide usable bandwidth of more than 200% (3-22.5 GHz). With two rod-shaped parasitic structures, frequency band-stop performance is generated, and characteristics such as band-notch frequency and bandwidth can be controlled. The designed antenna has a small size of 12 × 18 mm2 while showing the band-rejection performance in the frequency band of 5.1/5.9 GHz. The bandwidth of proposed antenna is wider than the bandwidth of antenna in the references.

Small modified monopole antenna for ultra-wideband application with desired frequency band-notch function

A novel printed monopole antenna for ultra-wideband applications with a frequency band-notch characteristic is presented. The proposed antenna consists of a stepped rectangular radiating patch and a modified ground plane that provides a wide usable fractional bandwidth of more than 120% (2.75–12.8 GHz). By cutting two rectangular slots with variable dimensions on the radiating patch, frequency band-stop performance is generated and we can control its characteristics such as band-notch frequency and bandwidth. The designed antenna has a small size of 12×20 mm2 while showing band rejection performance in the frequency band of 5.05–5.98 GHz.

Band-Notched Small Square-Ring Antenna With a Pair of T-Shaped Strips Protruded Inside the Square Ring for UWB Applications

A novel printed monopole antenna with constant gain over a wide bandwidth for ultra wideband applications with desired notch-band characteristic is presented. The proposed antenna consists of a square-ring radiating patch with a pair of T-shaped strips protruded inside the square ring and a coupled T-shaped strip and a ground plane with a protruded strip, which provides a wide us able fractional bandwidth of more than 130% (3.07-14.6 GHz). By using the square-ring radiating patch with a pair of T-shaped strips protruded inside it, the frequency bandstop performance is generated, and we can control its characteristics such as band-notch frequency and its bandwidth by electromagnetically adjusting coupling between a pair of T-shaped strips protruded inside the square ring. The designed antenna has a small size of 12 × 18 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , or about 0.15λ × 0.25λ at 4.2 GHz, while showing the band-rejection performance in the frequency band of 5.05-5.95 GHz.

Microstrip‐fed small square monopole antenna for UWB application with variable band‐notched function

AbstractIn this article, a novel square monopole antenna for ultra wideband applications with variable frequency band‐notch characteristic is presented. By using T‐shaped slots, additional resonances are excited and hence, the fractional bandwidth is increased up to 150%. A modified T‐shaped conductor‐backed plane is used to generate the frequency band‐stop performance. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 2065–2069, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25395

Ultra-wideband band-notched printed monopole antenna

A novel printed monopole antenna for ultra-wideband applications with variable frequency band-notch characteristics is presented. The proposed antenna consists of a beveled shape rectangular patch with a novel trident-shaped feeding structure and a truncated ground plane which provides a wide usable fractional bandwidth of more than 125% (2.8–12.6 GHz). By inserting a semi-octagonal parasitic strip to the antenna, a frequency band-stop performance is achieved and the authors can control its characteristics such as band-notch frequency and its bandwidth. The designed antenna has a small size of 22×25 mm2 while showing the band rejection performance in the frequency band of 5.1–6 GHz.

ULTRA-WIDEBAND SMALL SQUARE MONOPOLE ANTENNA WITH VARIABLE FREQUENCY BAND-NOTCH FUNCTION

In this paper, a novel printed monopole antenna for ultra wideband applications with variable frequency band-notch characteristic is presented. The proposed antenna consists of a stepped square radiating patch with modifled W-shaped slot and a ground plane with rectangular sleeve and pair of L-shaped resonator which provides a wide usable fractional bandwidth of more than 130% (3.05{14.3GHz). By cutting a modifled W-shaped slot with variable dimensions on the radiating patch frequency band-stop performance is generated and we can control its characteristics such as band-notch frequency and its bandwidth. The designed antenna has a small size of 12 £ 18mm 2 while showing the band rejection performance in the frequency band of 5.08 to 5.91GHz.

A Novel Band-Notched Planar Monopole Antenna for Ultrawideband Applications

In this letter, a novel planar monopole antenna with a variable frequency band-notch characteristic for ultrawideband (UWB) applications is presented. The UWB property is achieved by embedding two shorted rectangular quarter-wavelength resonators. Two other L-shaped quarter-wavelength resonators coupled to the radiating patch are also used in order to generate the frequency band-stop performance and control antenna characteristics such as band-notch frequency and its bandwidth. The designed antenna has a stopband of 5-5.9 GHz while maintaining wideband performance from 3.1 to 11 GHz with VSWR <; 2.

Small Square Monopole Antenna for UWB Applications With Variable Frequency Band-Notch Function

In this letter, a novel printed monopole antenna (PMA) for ultrawideband (UWB) applications with variable frequency band-notch characteristic is presented. The proposed antenna consists of a stepped square radiating patch with two U-shaped slots and a notched ground plane with a T-shaped sleeve that provides a wide usable fractional bandwidth of more than 140% (2.8516.73 GHz). By cutting two modified U-shaped slots with variable dimensions on the radiating patch, frequency band-stop performance is generated, and we can control its characteristics such as band-notch frequency and its bandwidth. The designed antenna has a small size of 12 times 19 mm2 while showing the band rejection performance in the frequency band of 5.02-5.97 GHz.

A Small UWB CPW-fed Monopole Antenna with Variable Notched Bandwidth

A compact ultra-wideband (UWB) CPW-fed monopole antenna with variable frequency band-notch characteristics with small size of 21.5 × 21 × 1 mm3 is presented. The antenna consists of a modified V-shaped patch and window-shaped conductor back plane with variable dimensions, which is used in order to generate the frequency band stop performance. The antenna is designed and measured successfully. The measured results show that this antenna operates over the frequency band between 2.7 and 11.5 GHz for VSWR < 2 while showing the band rejection performance in the frequency band of 5.1 to 5.9 GHz.

Novel Modified UWB Planar Monopole Antenna With Variable Frequency Band-Notch Function

A novel modified microstrip-fed ultrawideband (UWB) planar monopole antenna with variable frequency band-notch characteristic is presented. By inserting two slots in the both sides of microstrip feedline on the ground plane, much wider impedance bandwidth can be produced. A modified H-shaped conductor-backed plane with variable dimensions is used in order to generate the frequency band-stop performance and control its characteristics such as band-notch frequency and its bandwidth. The designed antenna has a small size of 22 x 22 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and operates over the frequency band between 3.1 and 14 GHz for VSWR < 2 while showing the band rejection performance in the frequency band of 5.1 to 5.9 GHz.