Embodiments are provided for an agile antenna that beamsteers radio frequency (RF) signals by selectively activating/de-activating tunable elements on radial-waveguides using direct current (DC) switches The antenna comprises two parallel radial waveguide structures, each comprising a first radial plate, a second radial plate in parallel with the first radial plate, and conductive elements positioned vertically and distributed radially between the two plates The radial waveguide structure further includes a plurality of quarter RF chokes which are connected to the conductive elements via respective micro-strips and tunable elements The two parallel radial plates are separated by a height determined according to a desired transmission frequency range for RF signals, a length of the micro-strips, a diameter of the conductive elements, and a clearance space around each one of the conductive elements

Apparatus and method of a dual polarized broadband agile cylindrical antenna array with reconfigurable radial waveguides

A novel compact size ultrawide band planar antenna with band notched characteristics is present. The band rejection characteristic is achieved by loading a pair of metamaterial inspired rectangular split ring resonator (SRR) near the feed line and by etching the SRR slots on a radiating patch. The simulated and measured results reveal that the proposed antenna exhibits the impedance bandwidth over the ultrawide band (UWB) frequency range from 3.1 to 14 GHz with the voltage standing wave ratio less than 2 except for band stop bands at 3.29 to 3.7 GHz (WiMAX band), 3.7 to 4.10 GHz (C-band), 5.1 to 5.9 GHz (WLAN band), and 7.06 to 7.76 GHz (downlink X-band satellite communication), respectively. The proposed antenna fabricated on low-cost FR-4 substrate has compact size of 24 × 20 × 1.6 mm3. The simulation results are compared with measured results and demonstrate good agreement with stable gain over pass bands. The proposed antenna also exhibits dipole-like radiation pattern in E-plane and omni-directional pattern in H-plane. These results led to conclusion that the presented antenna is a suitable candidate for ultrawide band UWB applications with desired band notch characteristics.

/pdf/compact-ultrawide-band-metamaterial-inspired-split-ring-451ns5p1o0.pdf

Compact Ultrawide Band Metamaterial-Inspired Split Ring Resonator Structure Loaded Band Notched Antenna

Auditory system in animals can capture external sound signals, which can be converted into biophysical electric signals, and then the auditory neurons are activated to generate kinds of firing patterns. Bats can detect signals with ultrahigh frequency while human auditory system is sensitive to sound and voice within the frequency range 20 to 20,000 Hertz. In this paper, a piezoelectric neuron is proposed to investigate the physical mechanism for selection of frequency and filtering in auditory wave, and filtering wave function is designed to simulate the mode selection in the electrical activities of auditory neuron. Sound signals with multiple frequencies are imposed to drive the auditory neuron and mode selection is analyzed in detail. A decay factor is introduced to control the wave filter and frequency selection, and the amplitude is decreased sharply within transient period when the frequency is beyond or below the threshold. Furthermore, additive noise is accompanied by the sound signals and the mode selection is investigated by taming the noise intensity carefully. It is found that intermediate noise intensity can enhance nonlinear resonance and the auditory wave is encoded to induce regularity in the neural activities. The results can be helpful for further designing smart sensor and wave filter in signal processing, and the biophysical mechanism for signal processing in auditory system is clarified.

Biophysical mechanism of signal encoding in an auditory neuron

2013 IEEE Symposium on Wireless Technology and Applications (ISWTA)

In this paper, a dual notch Ultra Wideband (UWB) monopole antenna with compact dimensions of 37.8 × 27.1 × 1.6 mm3 is presented. Octagon patch with a defected ground structure is used to attain the wide frequency range of 3.17 GHz–11.61 GHz with ultra-wide impedance bandwidth of 8.33 GHz. The band notch characteristics in WiMAX (3.2 GHz–3.67 GHz) and WLAN (4.32 GHz– 5.81 GHz) bands are achieved using inverted pi-slot in the radiating element and a pair of double split ring resonators (DSRRs) on either sides of the feed, respectively. Reconfigurability in the bands is obtained by using BAR64-03W pin diodes switching at the appropriate placement in the antenna structure. The proposed antenna exhibits efficiency of 88% in operating and 20% in nonoperating frequencies. The proposed antenna is designed, simulated, and optimized using HFSS 19 electromagnetic tool. The measured results are tested using combinational analyzer in a chamber with antenna measurement setup for validation and found in good matching with simulation.

/pdf/design-and-analysis-of-a-compact-reconfigurable-dual-band-1pfpoy51m3.pdf

Design and Analysis of a Compact Reconfigurable Dual Band Notched UWB Antenna

A design and analysis of broadband high isolation of discrete packaged PIN diode Single-Pole Double-Throw (SPDT) switch is presented. Many applications of wireless data communication are implementing Time Division Duplex (TDD) switching such as UMTS-TDD (in 3G technologies), LTE (in 4G technologies), HiperLAN, HiperMAN, WiFi, WiMAX and WiBRO. A broadband high isolation of SPDT switch is needed to provide these multimarket applications at different frequency bands. In this paper, three different circuit topologies (Type A, Type B and Type C) targeted for broadband high isolation are designed and analyzed. The SPDT switches are based on the discrete packaged PIN diode that available in the market for switching control. Analysis of the various configurations is done in order to select the most suitable topology for broadband high isolation SPDT switch. As results, Type C has been chosen for prototyping and measurement. In simulation and measurement, the isolation is higher than 25 dB from 0.5 to 3 GHz compared with Type A and Type B.

Design and analysis of broadband high isolation of discrete packaged PIN diode SPDT switch for wireless data communication

This paper presents the design of reconfigurable defected ground structure (DGS) resonator that can be integrated with ultrawide-band (UWB) microwave filter to produce bandpass and bandstop response simultaneously. The reconfigurable DGS is designed based upon coplanar waveguide (CPW) technology to exhibit bandstop characteristic at 3.5 GHz and 5.5 GHz using FR-4 on a 1.6 mm dielectric substrate thick with dielectric constant e r = 4.6. The simulation performance shows promising results that could be further validated during the experimental works. This topology of reconfigurable DGS is useful for applications when the undesired signals need to be removed such as in wideband systems.

Design of reconfigurable defected ground structure (DGS) for UWB application

This study presents a novel technique for designing an ultra-wideband (UWB) filteringantenna with dual sharp band notches. This design is composed of a modified monopole antenna integrated with resonant structures. The monopole antenna is modified using microstrip transition between the feedline and the patch. In addition, block with a triangle-shaped slot is loaded on each side of the ordinary circular patch to produce wide bandwidth with better return loss and higher frequency skirt selectivity. The resonant structures are constructed using two double split ring resonators (DSRR) loaded above the ground plane of the antenna to produce dual band notches and filter out WiMAX (3.3–3.7GHz) and HiperLAN2 (5.4–5.7GHz) frequencies. The band notch position is controlled by varying the length of the DSRR. The reconfigurability feature is achieved by using two PIN diode switches employed in the two DSRR. The measured results show that the proposed filtering-antenna provides wide impedance bandwidth from 2.58 to 15.5GHz with controllable dual sharp band notches for WiMAX and HiperLAN, peak realized gain of 4.96 dB and omnidirectional radiation pattern.

/pdf/a-novel-reconfigurable-uwb-filtering-antenna-with-dual-sharp-43437gvr3i.pdf

A Novel Reconfigurable UWB Filtering-Antenna with Dual Sharp Band Notches Using Double Split Ring Resonators

This paper demonstrates a reconfigurable dual-mode ring resonator matched bandstop filter. The dual-mode ring resonator structure is composed by two degenerate modes or splitting resonant frequencies using a perturbing stub. The reconfigurable dual-mode ring resonator matched bandstop filter is realized by using PIN diodes as switching elements. This reconfigurable filter provides two states of operation; allpass and bandstop response. Frequency of 1 GHz is chosen to demonstrate this operation. The theoretical analysis together with simulation and measurement results are presented in this paper. As a result, this filter can be reconfigured between allpass and bandstop using PIN diodes at 1 GHz.

Reconfigurable dual-mode ring resonator matched bandstop filter

This paper demonstrates a reconfigurable matched bandstop filter. The filter is based on a lossy allpass network. The lossy allpass network demonstrates the concept and design of perfectly matched bandstop response with a perfect matched at all frequencies. The filter is based on the half-wavelength λ over 2 resonator with gap coupling, parallel with an allpass nominally-90°-phase-shift element, which can be optimized to achieve high Q-factor. The reconfigurable matched bandstop filter can be realized by using PIN diodes as a switching element. This filter provides two state of operation under two conditions. The first condition is that the filter will produce allpass response when the PIN diodes are turned ‘ON’. The second condition is that the filter will produce bandstop response when the PIN diodes are turned ‘OFF’. Theoretical analysis together with experimental results is presented in this paper.

Noor Azwan Shairi

Papers

Design and analysis of broadband high isolation of discrete packaged PIN diode SPDT switch for wireless data communication

Design of reconfigurable defected ground structure (DGS) for UWB application

A Novel Reconfigurable UWB Filtering-Antenna with Dual Sharp Band Notches Using Double Split Ring Resonators

Reconfigurable dual-mode ring resonator matched bandstop filter

Reconfigurable matched bandstop filter