Return loss

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

The development of curved microstrip antenna with defected ground structure

Abstract: A series of curved microstrip antennae with defected ground structure for multiband are proposed, which are more smaller, conveniently conformal, wider radiation beam and suitable for WLAN terminal for difierent environment. The relation between the main geometry parameters and the antennas' characters are studied with the cavity model method and EM simulation, and the optimum size antenna is achieved later. If keeping the other parameters but increasing the curving angle fi, the return loss is almost good at f = 2:45GHz, but poor at f = 5:25GHz and 5.8GHz. After slight tuning the key parameters, these curved antennae all can work at f = 2:45GHz, 5.25GHz and 5.8GHz, and their patterns in the plane that is vertical to the curve axes become more wider or even omni- directional with the curving angle fi increasing, which are verifled by experiment, their measured gain are 2dB{6.3dB.

Millimeter-Wave Reflective-Type Phase Shifter in CMOS Technology

Abstract: The design and measurement of a compact, wide-band reflective-type phase shifter in 90 nm CMOS technology in V-band frequency is presented. This phase shifter has a fractional bandwidth of 26% and an average insertion loss of 6 dB over all phase states. The chip area is only 0.08 mm 2. Measurement results show that the developed phase shifter provides 90° continuous phase shift over the frequency range of 50-65 GHz. The measured return loss is greater than 12 dB at 50 GHz. The output power is linear up to at least 4 dBm input power.

Bandpass Filter With Tunable Bandwidth Using Quadruple-Mode Stub-Loaded Resonator

Abstract: In this letter, a novel quadruple-mode resonator bandpass filter (BPF) with tunable bandwidth is proposed. By using two types of microwave varactors to tune the resonant frequencies and transmission zeros (TZs), the high-side edge of the passband and low-side edge of the passband can be separately varied. Therefore, the bandwidth could be tunable with reasonable adjust of the values of varactors. Theoretical expressions have been derived for the resonant frequencies and the TZs. The measured results of the BPF show that the fractional bandwidth can be tuned from 22% to 34% at a fixed centre frequency 2.0 GHz with a return loss better than dB. The tested results show good agreement with simulated results.

A Wideband Common-Mode Suppression Filter for Bend Discontinuities in Differential Signaling Using Tightly Coupled Microstrips

Abstract: A new type of bend is proposed that reduces differential-to-common mode conversion occuring at the bend discontinuity in coupled microstrip lines for high-speed digital circuits. Simultaneously, great care has been taken to minimize the differential reflection coefficient and insertion loss, leading to an overall improved signal integrity. This is achieved by tapering the microstrip lines to tightly or very tightly coupled ones in the area of the bend. Full-wave simulations in the DC to 6 GHz frequency range show that over 9 dB and 14 dB suppression of conversion noise is achieved for tightly coupled and very tightly coupled bends, respectively. Also for these new structures, with a total length of 100 mm, the insertion loss remains below 0.6 dB. Measurements on prototype bends show very good agreement with full-wave simulations. Also time domain measurements demonstrate the significant reduction in conversion noise while keeping return loss low. Moreover, for design purposes, a dedicated circuit model which closely matches the full-wave characteristics of the proposed bends is presented.

30 GHz tuned MEMS switches

Abstract: This paper demonstrates the use of resonant tuning in high-isolation reflective MEMS electrostatic switches. Tuned switches can achieve higher isolation and a lower pulldown voltage than a comparable single element switch. An equivalent circuit model was developed for individual shunt capacitive membrane switches and then implemented in tuned circuits. The novel cross switch was developed on a high resistivity silicon. The cross switch attained an insertion loss of less than 0.6 dB and a return loss below -20 dB from 22-38 GHz in the up-state, and a down-state isolation of 50 dB with only 1.1 pF of down-state capacitance (Cd) per element. The pulldown voltage is 15-20 V, which is much better than typical industry numbers of 28-50 V. Application areas are low-loss high-isolation communication switches at 28 GHz and automotive switches at 77 GHz.