Integrated Filtering Antenna Research Articles

Filtenna Designed with Defected Ground Structure (DGS) for Ultra-wideband Applications

In microwave imaging applications, filter and antenna are the key components as front-end devices and function independently. Antenna radiates and receives signals to or from nearby scattered objects while filter is used to suppress unwanted signals noise before and after the required bandwidth. Current antennas suffer from high loss, bandwidth limitation and impedance mismatch and deteriorate their performance near the band-edges if connected as a stand-alone device. Due to the current trend towards simplicity and size reduction, researchers are focusing on integrating the filter and antenna into a single module called integrated filter-antenna (IFA) or filtering antenna (filtenna). These would improve the noise performance of the system and pre-filtering requirements such as complexity algorithm in inverse scattering techniques This paper introduces a novel contribution in the field of UWB antenna design by incorporating Defected Ground Structure (DGS) on both the antenna and filter. Thus, the main aim of this research is to conduct detail parametric studies of the proposed integrated filter-antenna with defected ground structure (DGS) to enhance the performance of imaging system. The proposed IFA will be analysed on Rogers RO4003C dielectric substrate by using EM tool, Computer Simulation Technology (CST) and measured using R&S Vector Network Analyzer (VNA). A compact ultra-wideband (UWB) filter and UWB elliptical antenna are designed and examined in detail before combining the devices. Different types of DGS are designed and act as the ground layer of the proposed filtering antenna. The bandwidth of each design is then compared with and without the existence of DGS. The results show that the proposed IFA with DGS implementation achieve the targeted objective, with compact size, enhanced bandwidth and better performance compared to the conventional design of filter and antenna. By integrating filter and antenna into one subsystem, it can help to reduce the loss and enhancing the bandwidth of the system thus letting the antenna to operate at more different frequencies that fall within the range. Both simulated and measured results prove that by integrating filter and antenna into one module, a low loss and larger bandwidth can be accomplished. High performance compact IFA can act as microwave transceiver to improve the overall performance of the microwave imaging system, MIS.

A novel bandpass filter fed antipodal tapered slot antenna for millimeter wave imaging

In this paper, we propose antipodal tapered slot antenna with integrated bandpass filter over 23.5–40 GHz for high resolution imaging applications. The novel antenna feed comprises of half mode substrate integrated waveguide and rectangular slots with isosceles trapezoidal variation. The feed section gives a passband over 23.5–40 GHz with S 11 <−10 dB and S 21 ≃0 dB. We present the design evolution procedure for the integrated filter antenna. The proposed antenna exhibits S 11 <−10 dB over the controlled bandwidth from 23.5 GHz to 40 GHz. We incorporate rectangular corrugations in the form of a staircase at the outer edges of the antenna and ground plane slots to achieve a stable gain and stable radiation pattern over the controlled bandwidth. The proposed antenna occupies a volume of 30.3 × 16 × 0.254 mm3, and is fabricated and tested. The measured results show good agreement with simulations. As compared to the state-of-the-art approaches, the proposed antenna is compact in size and exhibits a constant gain and stable radiation pattern over the operating bandwidth. We describe case studies to illustrate the application of the proposed antenna in a wideband imaging system for the detection of concealed objects and material defects. The reconstructed images obtained with the proposed antenna demonstrate its potential for use in high-resolution millimeter wave imaging systems.

Circularly polarized ultra–wide band filtering antenna with controllable band-notch for wireless communication system

A UWB filtering antenna (or filtenna) with a band-notched characteristic has been proposed in this paper. A square-shaped-stepped patch UWB antenna and an inverted T--shaped bandpass filter based integrated filtering antenna (IFA) with band-notch characteristic has been designed and fabricated. The size of the proposed filtenna is the same as the UWB patch antenna. The UWB patch antenna has a bandwidth from 3 GHz to more than 14 GHz. A UWB filter having a notched band is proposed and integrated with the primarily offered square-shaped--stepped patch antenna to design an IFA for UWB wireless communication system. The filter is placed on the feeding position of the patch antenna, and the output of the filter is coupled with the radiating patch to achieved the desired result. Proposed filtenna achieves circular polarization, minimum of 14 dB out of band gain rejection, and a notched band from 5.55 to 6.98 GHz, which avoids the interference from Dedicated Short Range Communication (DSRC) applications. A wide axial-ratio bandwidth (AXBW) from 3.1 to 5.5 GHz and 7–9.8 GHz along with a maximum gain of 6.8 dBi within the operating frequency range of the proposed filtenna has been achieved.

Slot Antenna Array with Integrated Filter for WLAN Application at 5.2 GHz

This paper deals with the design of a $$2\times 2$$ Integrated Filter Antenna array working at 5.2 GHz for IEEE 802.11a WLAN application. The filtering action is incorporated into the conventional antenna array, rendering enhanced selectivity and sharper gain roll-off than the conventional approach. An equivalent circuit model is extracted to validate the working of the proposed design. Fractional band width of $$3.0\%$$ around 5.2 GHz (ranging between 5.15 and 5.31 GHz) and maximum gain of 11.11 dBi is obtained through this design.

Integrated Open Loop Resonator Filter Designed with Notch Patch Antenna for Microwave Applications

This paper presented the design of integrated open loop resonator bandpass filter with notch type antenna for the use in microwave applications. Chebyshev type filter is selected as the filter characteristics and cascaded design with the antenna to produce a single module, Integrated Filter Antenna (IFA). Special feature of the antenna is the implementation of notch on the patch antenna to improve the efficiency. IFA is then simulated in electromagnetic simulation tool, Agilent Advance Design System (ADS) version 2016 and measured using R&S Vector Network Analyzer. It shows that the proposed IFA produced good measured return loss >-30dB with both vertical and horizontal gain of 9.11dBi and 8.01dBi respectively.

Highly selective integrated filter antenna for UWB application

ABSTRACTAn ultrawideband (UWB) integrated filter antenna (IFA) with enhanced selectivity is proposed. A circular radiating patch is electromagnetically coupled to a UWB filter. The design provides a fractional bandwidth of 109.5% covering the entire UWB region (3.1–10.6 GHz). The peak gain of the IFA varies between 3.0 and 4.0 dBi in the desired band with efficiency of more than 90%. The gain of proposed structure is same as that of a reference standalone monopole antenna in the desired frequency band, with a decrease beyond the cut‐off frequencies. The subsystem described in this article is compact, as it does not involve any additional line to integrate the antenna and filter. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:1032–1037, 2017

Integrated Filtering Antenna with High Selectivity Band Rejection for UWB Applications

Integrated Filtering Antenna with High Selectivity Band Rejection for UWB Applications

Design of Integrated Open Loop Resonator Bandpass Filter Antenna for 2.4GHz Applications

This paper presented the design of integrated filter antenna for 2.4GHz microwave applications. Open loop resonator bandpass filter is designed to increase the bandwidth of the antenna by producing the range of frequencies that can be accepted by the antenna structure. Direct connection between the filter structure and antenna may cause impedance mismatch and deteriorates the performance of both antenna and filter. Thus, by integrating both filter and antenna into a single module, the overall performance can be improved and increase the efficiency of the system with improved bandwidth. The design used FR4 with dielectric constant of εr = 4.7 with substrate thickness of 1.6mm. It is shown that the simulation result for the proposed integrated filter antenna produce return loss, S11=-20.009dB, gain of radiation pattern is 3.36dB and an increase of bandwidth to approximately 3.74% compare to the single structure antenna.

A Codesigned Compact Dual-Band Filtering Antenna with PIN Loaded for WLAN Applications

A codesigned compact dual-band filtering antenna incorporating a PIN diode for 2.45/5.2 GHz wireless local area network (WLAN) applications is proposed in this paper. The integrated filtering antenna system consists of a simple monopole radiator, a microstrip dual-band band-pass filter, and a PIN diode. The performance of the filtering antenna is notably promoted by optimizing the impedance between the antenna and the band-pass filter, with good selectivity and out-of-band rejection. The design process follows the approach of the synthesis of band-pass filter. In addition, the PIN diode is incorporated in the filtering antenna for further size reduction, which also widens the coverage of the bandwidth by about 230% for 2.4 GHz WLAN. With the presence of small size and good filtering performances, the proposed filtering antenna is a good candidate for the wireless communication systems. Prototypes of the proposed filtering antenna incorporating a PIN diode are fabricated and measured. The measured results including return losses and radiation patterns are presented.

Miniaturized Parallel Coupled-Line Filter-Antenna With Spurious Response Suppression

In this letter, a novel miniaturized integrated filter-antenna (IFA) module with dual-band filtering response is proposed. By controlling the open stub of the bandpass filter (BPF) over the antenna slot, its intrinsic band-gap characteristic helps suppressing the high-order spurious. A prototype IFA is designed and experimentally characterized. The dual-band BPF of the proposed IFA is arranged in an arc structure and is operated at 870 MHz and 2.42 GHz with fractional bandwidth 10.3% and 3.9%, respectively, leading to 62.3% size reduction compared to the conventional structure. The impedance bandwidth of the slot antenna is 3.9% with center frequency of 4.06 GHz. The antenna slot provides a good suppression of the spurious passband at 3.57 GHz around 17.3 dB.

Ultrawideband microstrip integrated‐antenna‐filter

AbstractA new three‐port integrated‐antenna‐filter (IAF) module is proposed for ultrawideband applications.The IAF is designed by closely packing a slot antenna and a patch filter on a single substrate. The reflection coefficient, mutual coupling, input impedance, radiation pattern, and insertion loss of the proposed configuration are studied. Since it was found that the mutual coupling between antenna and filter parts of the IAF is very small across a very wide bandwidth, the two parts can be designed almost independently. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:32–34, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25665

Compact Three-Port Integrated-Antenna-Filter Modules

In this letter, two novel three-port integrated-antenna-filter (IAF) modules are proposed. The idea of the IAF is elucidated with two configurations that consist of different combinations of narrow- and wideband microstrip/slot resonators. The return loss, mutual coupling, input impedance, radiation pattern, and insertion loss of the proposed configurations are analyzed. It was found that the mutual coupling between the antenna and filter parts of the IAF is very small; therefore, the two parts can be designed almost independently. As the three-port IAF module is compact and cost-effective, it should be useful for miniaturizing the circuit size of system-on-package (SOP) devices.

A millimetre-wave bandpass filter–lens array

A filter–lens array (FLA) is a planar array of bandpass integrated antenna–filter–antenna (AFA) elements which are stagger-tuned in the vicinity of a centre frequency, so as to provide the phase shift required for transforming spherical and planar wavefronts. Due to the filtering response of the AFA elements, FLA presents a bandpass gain and can act as a combination of a conventional lensarray and a filter. An FLA structure is demonstrated with f/D=1.25 and 8.2% bandwidth at 35 GHz. This FLA is composed of 137 AFA elements and fabricated on two three-inch glass wafers ($\epsilon_{r}=4.45$). A gain of 25.6 dBi and a total efficiency of 45% have been measured at 35 GHz. The Ka-band FLA shows a low-loss scanning performance for up to at least ±30° in the H-plane and ±20° in the E-plane.