Package-induced cross-coupling effect on amplifier harmonic suppression

2006 ◽  
Vol 49 (2) ◽  
pp. 332-336
Author(s):  
Han-Jan Chen ◽  
Tsung-Hui Huang ◽  
Chin-Sheng Chang ◽  
Lih-Shan Chen ◽  
Jui-Hong Horng ◽  
...  
Keyword(s):  
Coupling Effect ◽  
Cross Coupling ◽  
Harmonic Suppression

Dither in a rolling airframe flight vehicle with a two-position actuator: An amplitude distribution approach

2016 ◽  
Vol 39 (8) ◽  
pp. 1205-1215 ◽  
Author(s):  
Bahram Mohammadi ◽  
Mohammad Reza Arvan ◽  
Yousof Koohmaskan
Keyword(s):  
High Frequency ◽  
Degrees Of Freedom ◽  
Coupling Effect ◽  
Cross Coupling ◽  
Amplitude Distribution ◽  
Feedback System ◽  
Flight Vehicle ◽  
Frequency Signal ◽  
High Frequency Signal ◽  
Minimal Error

Rolling airframe manoeuvring is a type of manoeuvre in which the missile provides continuous roll during flight. Cross-coupling between the angle of attack and sideslip in rolling airframe missiles (RAMs) yields a coning motion around the flight path. As the pitch and yaw cross-coupling effect decreases, the radius of this coning motion decreases and the accuracy of the control system increases. Two-position (on–off) actuators are used in most RAMs. The presence of a two-position actuator in a feedback system makes its characteristics non-linear. A high-frequency signal so-called dither is applied to compensate for the non-linearity effect of the actuator characteristic in the feedback system and to stabilize the coning motion. The amplitude distribution function (ADF) method in dither analysis shows that the smoothed non-linearity characteristic can be computed as the convolution of the original non-linearity and the ADF of the dither signal. According to the four-degrees-of-freedom (4-DOF) equations of RAMs in a non-rolling frame and regarding various dither signals through the ADF approach on a two-position actuator, an analytical condition for dither amplitude in coning motion stability of RAMs is derived. It was shown that the triangular signal with specified amplitude and high enough frequency led to a smoother response of two-position actuators. Finally, by applying beam-riding guidance to a RAM, the performance of dithers for decreasing the distance of the missile from the centre of the beam is validated through simulations. It is illustrated that applying the triangular dither resulted in minimal error.

Closed Loop Performance of a Slotless Lorentz Self-Bearing Motor

2003 ◽  
Author(s):  
Hooi-Mei Chin ◽  
L. Scott Stephens
Keyword(s):  
High Speed ◽  
Closed Loop ◽  
Coupling Effect ◽  
Cross Coupling ◽  
Motor Design ◽  
High Speed Rotation ◽  
Bearing Stiffness ◽  
Speed Rotation ◽  
Power Densities ◽  
Tangential Directions

In previous work the authors presented a Lorentz self-bearing motor design targeted for precision pointing and smooth angular slewing applications. The motor also offers potential advantages when operated as a synchronous machine at high speed including larger power densities and shorter shafts. In this paper, the closed loop performance of the motor at low transient speeds (0–588 rpm) is presented. Using these results, several challenges to achieving high-speed rotation are identified and discussed. The most significant is the heavy cross coupling within the actuator which limits bearing stiffness and stability, and is amplified at rotor natural frequencies resulting in potential loss of levitation when passing through critical speeds. Of particular interest is the discovery of a significant cross coupling effect between the radial and tangential directions. A theory is put forth explaining this effect.

scholarly journals Design of Microstrip Patch Antenna with Enhanced Bandwidth and Harmonic Suppression for Wlan Applications

2020 ◽  
Vol 8 (5) ◽  
pp. 1642-1645
Keyword(s):  
High Frequency ◽  
Coupling Effect ◽  
Electromagnetic Coupling ◽  
Microstrip Patch Antenna ◽  
Simulation Software ◽  
Network Analyzer ◽  
Harmonic Suppression ◽  
Microstrip Patch ◽  
Rectangular Patch ◽  
Shorting Pin

A parallel combination of pair of λ/4 Resonator and the rectangular patch has enhanced the bandwidth and suppressed the unwanted harmonic radiations of the proposed antenna. Due to electromagnetic coupling effect, the pair of λ/4 resonator excites the radiating patch. Both λ/4 resonator and resonating patch excites at two different frequencies which are close to each other and this helps to increase the bandwidth of a proposed antenna. Also a shorting pin is used between the two λ/4 resonators which suppress the unwanted harmonic radiations. Design of a proposed antenna is done using the HFSS (High Frequency Simulation software). The Hardware results are observed on VNA (Virtual Network Analyzer).The operating frequency 3.6GHz.The proposed antenna is used in WLAN applicatio

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