Volume 74, Issue 5-6 -

In this paper, a new Wilkinson Power Divider ‎‎(WPD) using open and short stubs is proposed. ‎Open and short stubs are utilized instead of 1/4 wave transmission lines in initial ‎structure to achieve harmonics suppression. The proposed WPD is designed for ‎operational frequency of 0.9 GHz and creates 3 transmission ‎zeros at 1.8 GHz, 2.7 GHz and 3.6 GHz, for suppressing second, third and fourth harmonics. The proposed WPD has been fabricated and the ‎measurement results are in good accordance with simulation results. The designed ‎WPD has a 22 % fractional bandwidth with 0.1 dB insertion loss.‎

This article presents a design of highpass filter (HPF) for millimeter-wave (mm-wave) applications using a square complementary split-ring resonator (SCSRR). A miniaturized size HPF filter is obtained by overlapping the Right-Hand (RH) and Left-Hand material. The arrangement of inter-digital parallel coupled capacitor and SCSRR offers low insertion loss, high selectivity with a sharp roll-off factor over a wide bandwidth of 15.9 GHz (from 34.1 to 50 GHz). Generally, SCSRR offers narrow passband/stopband however this prototype has a passband over a wide range of frequency. The proposed HPF has an appreciable agreement between simulated and fabricated results. Further, the filter is realized in the equivalent circuit model and their electrical elements functions are also discussed. This prototype has a cut-off frequency (f c ) of 34.1 GHz with a maximum passband insertion loss of 1.45 dB. The fabricated area of the filter is 0.16λ g  × 0.09λ g  × λ g and where λ g is the guided wavelength at cutoff frequency f c .

Inspired by the theory of leaky wave antenna, a broadband and wide-angle frequency scanning antenna is proposed in this paper. My goal is to trade a narrow frequency band for a wide-angle beam scanning. Since the dispersion of spoof surface plasmon polariton (SSPP) mode slow-wave possesses larger gradient than that of the waves in the air, the metallic corrugated line (MCL) is adopted for energy transmission. To convert confined slow-wave into radiated fast-wave, a number of metallic patches are alternatively and periodically loaded besides the MCL and fed by electrically coupling. Owing to the frequency-dispersive phase difference between two patches, the resultant radiations are capable of beam scanning. As an example, the fabricated prototype operates in a relative bandwidth of 19.5 % (from 7.4 GHz to 9.0 GHz). Both the simulated and measured results have verified that the main beam of leaky-wave radiation can continuously scan from the backward direction to the forward direction with a scanning angular domain of 56° and an average gain level of 12.0 dB.

A broadband circularly polarized slotted square patch antenna with horizontal meandered strip (HMS) is presented and studied. The HMS feeding technique provides the good impedance matching and broadside symmetrical radiation patterns. A set of cross asymmetrical slots are etched on the radiating patch to realize the circular polarization. An electrically small stub is added on the edge of the antenna for further improvement in performance. Measured 10-dB impedance bandwidth (IBW) and 3-dB axial ratio bandwidth (ARBW) of the proposed antenna are 32.31 % (3.14–4.35 GHz) and 20.91 % (3.34–4.12 GHz), respectively. The gain of the antenna is varied from 3.5 to 4.86dBi within 3-dB ARBW. Measured results matched well with the simulated results.

In this paper, a novel compact UWB antenna with variable notched band characteristics for UWB applications is presented. The designed antenna primarily consists of an adjusted elliptical shaped metallic patch and a partial ground plane. The proposed antenna has a compact size of only 17 × 17 mm 2 . The suggested antenna covers the frequency range from 3.1 GHz to 12 GHz. A single notched band has been achieved at 7.4 GHz with the aid of integrating a novel closed loop resonator at the back plane of the antenna. This notched band can be utilized to alleviate the interference impact with the downlink X-band applications. Besides, a square slot was cut in the loop in order to obtain a variable notched band. With the absence and the existence of this slot, the notched band can be varied to mitigate interference of the upper WLAN band (5.72–5.82 GHz) and X-band (7.25–7.75 GHz) with UWB applications. A good agreement between measurement and simulation results was achieved, which affirms the appropriateness of this antenna for UWB applications.

A novel scheme to suppress the remnant mode conversion noise with a surface mount device (SMD) capacitor on dual back-to-back bent differential lines is proposed. To suppress the remnant mode conversion noise, an additional SMD capacitor is loaded on the differential lines between two bends to equalize even- and odd-mode velocities. The mode conversion noise suppression characteristics of the proposed scheme were analyzed and compared with various schemes. Also, eye diagrams confirmed that the addition of the SMD capacitor suppressed remnant mode conversion noise while preserving differential signal quality in dual back-to-back bent differential lines.

This paper presents a modern compact quad-band bandpass filter (BPF) using dual-mode stub loaded half wave (λ/2) resonators, where a couple of directly fed resonators are loaded with two identical inner resonators such that the direct fed resonators will act as feeding structure for the loaded resonators. Based on the proposed stub loaded resonators, a modern filter with seven transmission zeros (TZs) is designed by folding the two identical inner resonators. The proposed design has a symmetrical geometry, therefore even-odd mode analysis is used to predict the resonant frequencies of the passbands. The first and second passbands are obtained through fundamental odd and even modes respectively while the third one is achieved by placing loaded inner resonators in the proposed design. The second even harmonic of the direct fed resonators is utilized to achieve the fourth passband and is controlled by the stubs loaded at the middle of the resonators. The filter is simulated and fabricated for the purpose of validation, wherein a good agreement can be seen in both simulated and experimental results.