High isolation multiport integrated antenna system for cognitive radio applications

An ultra-wideband (UWB) planar monopole antenna integrated with a narrow-band (NB) cylindrical dielectric resonator antenna (DRA) is presented. The proposed antenna consists of a UWB monopole excited by a coplanar waveguide (CPW) transmission line, acting as a ground for a DRA excited by a slot. The mode HEM11- is excited in the NB DRA. To validate the concept of integration, an antenna is fabricated and measured. The measured results demonstrate that the UWB antenna provides a 2 : 1 voltage standing wave ratio (VSWR) bandwidth for 3.05{11GHz, integrated with a dual-band NB antenna. Moreover, the two ports have the same polarization and a reasonable isolation (less than i10dB) between each other. This is a promising candidate for applications in cognitive radio, where the UWB antenna can be used for spectrum sensing and the NB antenna for communication operation.

An integrated three-antenna structure for 5G, WLAN, LTE and ITU band cognitive radio communication

In this paper, a band-stop filter in Ka band is proposed, which is based on substrate integrated waveguide(SIW) resonators and complementary split ring resonators(CSRR). The SIW resonators filter is provided with high pass characteristics. We show that near the resonance point, the impedance characteristics is significantly increased by CSRR. Therefore, we can combine the SIW resonators and CSRRs to change the high pass characteristics and significantly improve the rejection level of the stop-band by etching CSRRs on the top layer in the SIW resonators. The simulated insertion loss of the filter is around 𢀒 1dB and the return loss is less than 𢀒15dB at the frequency range of 26 to 29 GHz and 32.5 to 36 GHz. In addition, the rejection level is above 𢀒20dB from 29.5 to 32GHz.

A novel tunable triple band-notch vivaldi antenna which can also be reconfigured as a tunable narrow band antenna is proposed in this paper. The triple band notch characteristic is obtained by placing three split ring resonators (SRR) on the slotline and tuning it using a varactor diode. A tuning range from 800 MHz-1.1 GHz is contributed by each of the three varactor loaded SRRs yielding an overall tuning range of 3.5 GHz. The gain of the standalone Vivaldi is around 6-7 dBi in the entire Ultra wide Band (UWB) spectrum. The same antenna is reconfigured into narrowband antenna by introducing switches on the slotline above the SRR. This reconfigurable antenna is suitable for both underlay and interweave spectrum access in Cognitive Radio.

The emerging feature-rich and high-data-rate wireless applications have put increasing demand on radio spectrum. The scarcity of spectrum and the inefficiency in its usage, as caused by the current radio spectrum regulations, necessitate the development of new dynamic spectrum allocation policies to better exploit the existing spectrum. The current spectrum allocation regulations assign specific bands to particular services, and grant licensed band access to licensed users only. Cognitive Radio (CR) will revolutionize the way spectrum is allocated. In a CR network, the intelligent radio part allows unlicensed users (secondary users) to access spectrum bands licensed to primary users, while avoiding interference with them. In this scheme, a secondary user can use spectrum sensing hardware/software to locate spectrum portions with reduced primary user activity or idle spectrum slots, select the best available channel, coordinate access to this channel with other secondary users, and vacate the channel when a primary user needs it. To achieve this, the transceiver in a CR system should have awareness of the radio environment in terms of spectrum usage, power spectral density of transmitted/received signals, and wireless protocol signaling, should be able to adaptively tune system parameters such as transmit power, carrier frequency, and modulation strategy. The transceiver should also be ended with an antenna system that can simultaneously operate over a wide frequency band (sensing) and a chosen narrow band (communication), or operate over an ultra-wide frequency band while possibly blocking signals in a narrow frequency range. Ultra-wideband (UWB) is a transmission technique that uses pulses with a very short time duration across a very large frequency portion of the spectrum. UWB is different from other radio frequency communication techniques in that it does not use RF carriers, but instead employs modulated high frequency pulses of low power with a duration of less than 1 nanosecond. From the perspective of other communication systems, the UWB transmissions are part of the low power background noise. Therefore UWB promises to enable the usage of licensed spectrum without harmful interference to primary communication systems, and can be used as an enabling technology for implementing CR. In this chapter, we offer a general overview of Cognitive Radio and dynamic spectrum access, discuss the advantages of using UWB as an enabling technology for CR, and give

A novel composite right-/left-handed transmission line (CRLH TL) and its equivalent circuit model are proposed based on cascaded complementary single split ring resonator (CCSSRR). It features an intrinsically balanced wider band and an additional transmission zero above the right-handed band relative to CRLH TL using complementary single split ring resonator and complementary split ring resonators. Moreover, two single negative (SN) metamaterial (MTM) TLs constructed by using complementary electric inductive-capacitive resonator on the conductor strip and on the ground, respectively, are researched. Both SN MTM TLs exhibit electric resonance above the fundamental magnetic resonance. For application, a monoband (MB) bandpass filter (BPF) covered WLAN band, and a dual-band (DB) BPF covered satellite DMB band and WiMAX band are designed, fabricated, and measured. The SN MTM TLs are adopted for the sake of deep and wide out-of-band suppression while CRLH MTM TLs using square-shaped and Sierpinski-shaped CCSSRR are critical factors of the MB and DB behavior. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2012. © 2012 Wiley Periodicals, Inc.

A novel ultra-wideband (UWB) antenna with double band-notched characteristics is proposed. Which based on Complementary split ring resonator(CSRR) and slots structure. The double band-notched characteristics are achieved by etching CSRR on radiating patch and slots on ground plane. The UWB antenna work effectively during 3.1GHz~14.4GHz, and realized characteristic of band-notched in frequency of 4.3~4.7GHz(INSAT), 6.8~7.1GHz (RADIO and TELEVISION), the frequency of the stop band can be adjusted by the length and width of etching slots. The simulated results indicate that the presented antenna has good radiation, ultra-wideband characteristic and has a monopole-like radiation patterns on pass band.

This paper presents a new compact ultra-wideband (UWB) microstrip antenna with Triple band-notched characteristics. This UWB antenna consists of Complementary Split Ring Resonator (CSRR) and C-shape slots on radiating patch to create triple band-notch characteristics in 3.3-3.6 GHz frequency band for WiMAX, C-band and 5.1-5.8 GHz for WLAN. The CSRR and C-shape slot effects exhibited by using vector surface current distribution. Presented compact structure shows the improved band notched characteristics and the good omnidirectional radiation patterns in the pass band. The proposed antenna is operated over 3 to 11 GHz for VSWR <; 2. All simulations in this work have been carried out by using the electromagnetic software Ansoft HFSS. CSRR slotted dual band notched antenna fabricated and measured to verify the concept and further it improved to create triple band notched characteristics.

&lt;span lang="EN-US"&gt;An antenna system that is reconfigurable in frequency is presented in this paper as a novel dual port design that serves both undelay and interweave cognitive radio. This 25×40×0.8 mm3 system is composed of two wide slot antennas: the first is designed as an ultra-wideband (UWB) antenna with controllable band rejection capabilities, while the second antenna is reconfigurable for communication purposes. Three slots are etched into the patch of the UWB antenna to obtain band notching in wireless local area network/Xband/International Telecommunication Union bands (WLAN/Xband/ITU) bands which can be controlled by a positive-intrinsic-negative (PIN) diode across each slot. The configuration states of these three diodes are all useable that produces seven band rejection modes plus the UWB operation mode. The second antenna is configured by five PIN diodes to operate either in Cband, WLAN or Xband regions which results in three interweave modes when setting the first antenna for UWB sensing. The design is simulated by computer simulation technology (CST) v.10. S21 results shows good isolation while input reflection coefficient and realized gain results prove system’s scanning, filtering and communication capabilities. This system is new that it gathers the undelay/interweave operation in a single design and when considering its large number of operation modes it looks adequate for many cognitive radio applications.&lt;/span&gt;

An ultra-wideband (UWB) planar microstrip antenna integrated with a narrow-band cylindrical dielectric resonator antenna (DRA) is presented for cognitive radio applications. The proposed antenna is a combination of semicircular-semi hexagon shape microstrip patch, which is fed by coplanar waveguide (CPW). The dielectric resonator antenna (DRA) is cylindrical in shape excited by a microstrip slot fed on the rear side which shows a narrow band (NB) characteristics. The microstrip antenna provides a wide bandwidth operates from 2.58 GHz to 14 GHz. The DRA provides a narrow bandwidth operates from 10.07 GHz to 11.38 GHz. The UWB antenna is used for sensing the spectrum and the narrow-band DRA used for communication operation. A very good isolation between the two antenna ports (S 21 less than −15 dB) are also achieved. Compared to the existing designs the peak gain of the antenna is highly increased around 6.15 dB.

An integrated antenna utilizing uniplanar nature of coplanar wave guide with wide and narrow band characteristics for category-A cognitive radios is presented. The space between two tapering which forms the ultra-wideband antenna (UWBA), where the surface current is minimum, is effectively used for the integration of a narrow band antenna (NBA). The UWBA and NBA provide 2:1 VSWR bandwidths from 2.7GHz to 11GHz and 5.0 GHz to 5.5GHz, respectively with isolation better than 15dB. The radiation characteristics are suitable for cognitive radio systems, where a UWBA is used for spectrum sensing and NBA for communication.

An ultra-wideband (UWB) dual-polarized microstrip slot antenna with high port isolation and planar structure is presented in this letter. This antenna consists of a monopole and a tapered microstrip feed line, they are used for obtaining UWB characteristic and generating two orthogonal polarization modes. Furthermore, the good impedance matching can be attained through etching slots on the ground plane. The simulated results point out that the antenna can cover the input impedance bandwidth of 3.1∼10.6 GHz with reflection coefficient <−10 dB, and the port isolation is better than 22 dB over the whole operating band. It also has a good radiation performance and is appropriate for UWB applications.

This work presents an innovative compact dual-band microstrip sensor based on a complementary split-ring resonator (CSRR) for the precise characterization of water–ethanol mixtures. The sensor, optimized via HFSS, offers high sensitivity and an impressive quality factor through dual-band operation at 3.5 GHz and 4 GHz. The validity of the sensor’s performance is supported by both simulated and measured results, which demonstrate its capacity to extract the complex dielectric permittivity of liquids. The proposed sensor utilizes CSRR and offers dual-band resonance, making it a promising alternative to traditional CSRR. This innovative sensor’s dual-band capability, achieved through its unique use of CSRR, renders it particularly suitable for applications in chemical and biomedical fields.

In this paper, a compact and low-profile tri-port antenna system is proposed for cognitive radio (CR) applications. The proposed system consists of a ultra-wide band (UWB) antenna fed by co-planar waveguide (CPW) structure and two meandered monopole antennas on the same substrate. The spectrum sensing is performed by UWB antenna (3.1 GHz - 10.1 GHz) and meandered antennas operates in several frequency bands for communication purpose. Without any decoupling structure the isolation level between UWB and meandered antennas is higher than 15 dB in the UWB frequency range. The measured S-parameters and radiation patterns are in good agreement with simulation results.

Metamaterial resonator based wave propagation notch for ultrawideband (UWB) filter applications is proposed. The presented filter combines a conventional bandpass characteristic and negative permittivity metamaterial to establish a UWB response and extra wave propagation notch to reject the HiPerLAN interference, without compromise in performance and size. The negative permittivity metamaterial is made of complementary split ring resonators (CSRRs), etched on the ground plane. In addition a new method is proposed, demonstrating a significant improvement in the matching between the CSRRs and the host transmission line. The measured results show that the filter has an insertion loss less than 1 dB and bandwidth of 8.4 GHz with 22 dB rejection at 5.4 GHz.