Return loss

About: Return loss is a research topic. Over the lifetime, 11090 publications have been published within this topic receiving 97603 citations.

A 60-GHz Millimeter-wave CMOS Marchand Balun

Abstract: A novel 60-GHz wideband Marchand balun fabricated with a standard 0.18 mum 6-metal-layer CMOS process for millimeter-wave applications is presented. A technique for achieving good balance with the fourth metal layer microstrip conductor is used in the designed Marchand balun. The fabricated CMOS balun uses multilayer coupling with the top two layers. An output matching network is added to improve the output return loss. The measured amplitude imbalance was about plusmn 1.5 dB from 25 to 65 GHz , over the 89% operating frequency band.

Design of a Broadband Eight-Way Coaxial Waveguide Power Combiner

Abstract: In this paper, a broadband high-power eight-way coaxial waveguide power combiner with axially symmetric structure is proposed. A combination of circuit model and full electromagnetic wave methods is used to simplify the design procedure by increasing the role of the circuit model and, in contrast, reducing the amount of full wave optimization. The presented structure is compact and easy to fabricate. Keeping its return loss greater than 12 dB, the constructed combiner operates within 112% bandwidth from 520 to 1860 MHz.

Tunable Bandpass Filter With Two Adjustable Transmission Poles and Compensable Coupling

Abstract: In this paper, tunable microstrip bandpass filters with two adjustable transmission poles and compensable coupling are proposed. The fundamental structure is based on a half-wavelength (λ/2) resonator with a center-tapped open-stub. Microwave varactors placed at various internal nodes separately adjust the filter's center frequency and bandwidth over a wide tuning range. The constant absolute bandwidth is achieved at different center frequencies by maintaining the distance between the in-band transmission poles. Meanwhile, the coupling strength could be compensable by tuning varactors that are side and embedding loaded in the parallel coupled microstrip lines (PCMLs). As a demonstrator, a second-order filter with seven tuning varactors is implemented and verified. A frequency range of 0.58-0.91 GHz with a 1-dB bandwidth tuning from 115 to 315 MHz (i.e., 12.6%-54.3% fractional bandwidth) is demonstrated. Specifically, the return loss of passbands with different operating center frequencies can be achieved with same level, i.e., about 13.1 and 11.6 dB for narrow and wide passband responses, respectively. To further verify the etch-tolerance characteristics of the proposed prototype filter, another second-order filter with nine tuning varactors is proposed and fabricated. The measured results exhibit that the tunable fitler with the embedded varactor-loaded PCML has less sensitivity to fabrication tolerances. Meanwhile, the passband return loss can be achieved with same level of 20 dB for narrow and wide passband responses, respectively.

Development of integrated three dimensional Bluetooth image reject filter

Abstract: We present the design and implementation of an S-band compact planar integrated filter integrated in a multi-layer ceramic substrate. The center frequency of the 3.8 mm/spl times/2.4 mm/spl times/0.5 mm front end image reject filter is 2.4 GHz, suitable for use in a Bluetooth wireless LAN transceiver system. Measurement results shows 3 dB insertion loss and 22 dB return loss at the center frequency.

Coplanar stripline to microstrip transition

Abstract: A new coplanar stripline to microstrip line transition is experimentally demonstrated and modelled using the finite difference time domain technique, The measured insertion loss and return loss for two back-to-back transitions with a short length of microstrip line in between are better than 2.4 and –10 dB, respectively, over the frequency range of 5.1 – 6.1 GHz. The bandwidth of the transition is ~18 % at a centre frequency of 5.55 GHz.