Zhang, T, Bao, J, Cai, Z, Yang, Y, Zhu, H, Zhu, X & Dutkiewicz, E 2018, 'A C-Band Compact Wideband Bandpass Filter with High Selectivity and Improved Return Loss', IEEE Microwave and Wireless Components Letters, vol. 28, no. 9, pp. 777-779.View/Download from: UTS OPUS or Publisher's site
© 2001-2012 IEEE. In this letter, a C-band compact wideband bandpass filter (BPF) with high selectivity and improved return loss (RL) is proposed. Two pairs of short-circuited stubs are employed on a transmission-line model to generate three transmission poles and two transmission zeros (TZs), where the odd-and even-mode analysis is used to analyze the resonant frequencies of the BPF. By applying the transversal signal-interference technique, two additional TZs can be generated in the upper and lower stopbands, respectively. The measured results show that the 3-dB fractional bandwidth is 62.8% at the center frequency of 5 GHz. The RL and the insertion loss within the passband are better than 22 and 0.6 dB, respectively. Moreover, the roll-off rate is up to 100 dB/GHz.
Zhang, T, Cai, Z, Yang, Y, Bao, J & Wang, Y 2017, 'Compact tunable lowpass filter with sharp roll-off and low insertion loss', Microwave and Optical Technology Letters, vol. 59, no. 10, pp. 2619-2623.View/Download from: UTS OPUS or Publisher's site
© 2017 Wiley Periodicals, Inc. A novel continuously tunable lowpass filter (LPF) with compact size, sharp roll-off and low insertion loss is presented in this paper. The filter employs two varactor diodes, a pair of open-ended coupled lines and a U-shape step impedance line (SIL) with an open-ended stub loaded at the center of the SIL to form a very compact layout. The odd- and even-mode analysis and equivalent circuit model are demonstrated for estimation of the transmission characteristics. Tuning the DC voltage applied on the varactor diodes, the varactor capacitance accordingly changes leading to a varying cutoff frequency f c . The measured results show that the achieved 3-dB f c tuning range is 60.6% (1.15–2.15 GHz). The measured insertion loss (IL) and roll-off rate are 0.2-0.4 dB and 50–73 dB/GHz, respectively. The overall size of the LPF is only 0.005λ g 2 , which shows a competitive advantage comparing with the state-of-the-art work.
Cai, Z, Lin, J, Zhang, T, Yang, Y, Liu, Y & Tang, X 2018, 'A low phase noise VCO employing tunable stubs loaded nested split-ring resonator', 2018 Australian Microwave Symposium, AMS 2018 - Conference Proceedings, Australian Microwave Symposium, IEEE, Brisbane, QLD, Australia, pp. 57-58.View/Download from: UTS OPUS or Publisher's site
© 2018 IEEE. In this paper, a low phase noise VCO employing tunable stubs loaded nested split-ring resonator (SLNSRR) has been proposed By loading anti-pair varactors at each side of the SLNSRR, the center frequency of the SLNSRR filter can be tuned from 1.82 GHz to 2.18 GHz. In the oscillator design, the tunable SLNSRR filter is used as a frequency stable element to select the oscillation frequency while keeping the low phase noise performance. To validate the method, an L-band to S-band VCO is designed, fabricated and measured. The measured results show that the proposed VCO has a frequency tuning range from 1.787 GHz to 2.117 GHz with a 16.9 % bandwidth. Over this frequency range, the phase noises measured at 1 MHz frequency offset are better than -113.49 dBc/Hz.
Zhang, T, Lin, J, Bao, J, Cai, Z & Yang, Y 2018, 'Design of voltage-controlled oscillator with compact size and wide tuning range', 2018 Australian Microwave Symposium, AMS 2018 - Conference Proceedings, Australian Microwave Symposium, Brisbane, QLD, Australia, pp. 59-60.View/Download from: UTS OPUS or Publisher's site
© 2018 IEEE. In this paper, a novel frequency-tunable filter based low noise voltage-controlled oscillator (VCO) is proposed. The proposed tunable filter consists of a T-type resonator with four varactors and a pair of short-ended stubs connected with feedlines. High-Q can be achieved by introducing a transmission zero on the upper stopband, which can reduce the phase noise of the VCO. The whole size of the tunable filter is 0.002λ2g. The proposed VCO was fabricated and measured indicating a promising frequency-tuning range from 2.2 to 3.2 GHz with the second harmonic suppression level of better than 22 dB. The measured phase noise is -88-91.44dBc/Hz at 100KHz offset.
Cai, Z, Tang, X, Zhang, T & Yang, Y 2018, 'An X-band Low Phase Noise Oscillator with High Harmonic Suppression Using SIW Quarter-Wavelength Resonator', IEEE MTT-S International Microwave Symposium Digest, IEEE/MTT-S International Microwave Symposium, IEEE, Philadelphia, PA, USA, pp. 427-430.View/Download from: UTS OPUS or Publisher's site
© 2018 IEEE. This paper presents a low phase noise oscillator with high harmonic suppression employing a pair of substrate integrated waveguide (SIW) quarter-wavelength resonators (QWR) in the feedback loop of the oscillator. By tuning the width of the SIW-QWR based filter, the stopband bandwidth can be extended while maintaining the high group delay in the passband. Taking advantages of the proposed SIW-QWR, an X-band low phase noise oscillator with the second and third harmonic suppression is designed, fabricated and tested. The measured results show that the oscillator operates at 8.08 GHz with -2.14 dBm output power. The second and third harmonic suppression of the presented oscillator can reach to 39.23 dB and 67.64 dB, respectively, with a single SIW-QWR filter. The phase noise performance of the proposed oscillator are -109.94 dBc/Hz at 100 kHz frequency offset and - 130.36 dBc/Hz at 1 MHz frequency offset, respectively.
Zhang, T, Yin, J, Cai, Z, Yang, Y & Bao, J 2018, 'X-Band Low Phase Noise Oscillator Based on Hybrid SIW Cavity Resonator', 2018 IEEE International Conference on Computational Electromagnetics, ICCEM 2018, IEEE International Conference on Computational Electromagnetics, IEEE, Chengdu, China.View/Download from: UTS OPUS or Publisher's site
© 2018 IEEE. In this paper, a compact X-band low phase noise oscillator based on a hybrid SIW cavity resonator is presented. This proposed resonator is composed of a circular waveguide cascaded by two rectangular waveguides. Two pairs of holes are embedded into the resonator to improve the Q-factor. Owing to the existence of discontinuous metal side walls, the fundamental mode TM-110 of the circular waveguide can be applied to design the oscillation frequency of the oscillator. The fabricated oscillator has been demonstrated to oscillate at 9.5 GHz. The phase noise is less than-112.84 dBc/Hz at 100 kHz offset with 1.67 dBm output power, exhibiting the figure of merit (FOM) of-202.06 dBc/Hz.