Papers by Keyword: L-Band

Abstract: In this paper, the performance of ring cavity Brillouin Erbium fiber laser (BEFL) within L-band wavelength region are discussed. Introducing Erbium doped fiber as a secondary gain medium into conventional Brillouin fiber laser configuration is the best alternative to maximize the Brillouin Stokes power (output power) and to sustain the gain flatness. Few parameters comprising length of fiber, pump power and tunable laser source power are varied to obtain the optimum output power. From the simulation process, a maximum Brillouin Stokes power of 54.75 dBm is produced as 16 dBm Brillouin pump power and 1480 nm pump laser are injected to the configuration.

Abstract: Frequency synthesizer provides frequency source for modern communication systems and computer systems. It is an essential part to the modern electronic system devices. This paper describes a wideband, frequency agile, low phase noise, low spurious frequency synthesizer. By using frequency multiplying technology, an S-band frequency source as the DDS clock is designed. The actual frequency source was tested. The test results show that the frequency synthesizer achieves the desired objectives.

Abstract: With the rapid development of wireless communications, there are more and more ​​stringent requirements on the wireless receiver, such as low power consumption, high reliability, low price, as well as smaller size. The design of RF receiver is the key to achieve this goal. According to the actual needs of the project, a double conversion IF receiver is designed. At first, the high frequency signal is changed to a higher IF, and the second output is a zero-IF signal. Experimental results show that the receiver has 100dB gain and a flat bandwidth.

Abstract: Trenched, vertical SiC static induction transistors (SIT) for L-band power amplification were fabricated with implanted p-n junction gates on conducting n-type 4H-SiC substrates using a self-aligned fabrication process. The self-aligned fabrication process required no critical alignments and allowed for high channel packing densities ranging from 2.9x103 to 5x103 cm/cm2. Devices were fabricated with a range of finger widths. Devices with the narrowest fingers were able to block up to 450 V with VGS = -3 V. Devices with wider fingers required higher gate voltages ranging from -10 V to -25 V to achieve similar blocking. Devices were packaged and small-signal and loadpull measurements were taken with the devices externally matched. Devices having the narrowest finger design had a small-signal power gain of over 9 dB at around 1.3 GHz. Load-pull measurements of packaged SITs with 1 cm gate periphery yielded a maximum power gain of ~ 8.2 dB at 1 GHz, VDD = 100 V, and VGS = 1.2 V. Due to the high packing density, these results translate to power densities of 22 kW/cm2.

Abstract: We report for the first time on RF SiC BJTs fabricated on semi-insulating (SI) substrates with L-band performance. Small-periphery (4x150μm) devices were tested using on-wafer load-pull measurements up to 1.5GHz. Under pulsed conditions, the devices exhibited 10dB of power gain at 1GHz and a peak power density of 2.3W/mm (1.4W) with a 100μs pulse width and a 1% duty cycle. The power gain decreased to 8dB at 1GHz under CW conditions at a power density of 1.6W/mm (1W). The load-pull measurements were performed up to 125oC, which resulted in a 1 dB reduction of power gain compared to the room temperature performance. Results at 0.5 and 1.5 GHz are presented as well.