Design And Development of A 6-Port Optical Circulator Using Silicon Photonic Crystals

A 6-port optical circulator using silicon photonic crystals has been designed and proposed in this paper as an essential component of an optical communication system. The proposed 6-port circulator has greater isolation loss values between the input and isolated ports and lower insertion loss values between the input and output ports. The proposed circulator achieves maximum isolation of -38.7 dB and minimum insertion loss of 0.0029dB. The proposed designs are extremely useful in the telecommunications industry, wavelength division multiplexing and photonic integrated circuits applications due to their low insertion and high isolation losses.

Fiber loop ring-down spectroscopy with a long-period grating cavity

Cavity Ring-down spectroscopy is an absorption detection technique that makes the[sic]use of an optical cavity to realize a long effective optical path length through a sample and to render the measurement independent of intensity. These two features give the ring-down spectroscopy many advantages over traditional absorption techniques and allow it to measure chemicals present in trace amount. This thesis presents my study of fiber loop ring-down spectroscopy with a long-period grating (LPG) cavity as the sensing section. There are several advantages in this design: 1) It provides a relatively larger sensing area for the evanescent wave to interact with the environment when compared with a fiber taper and a D-shaped fiber; 2) The LPG cavity has a much lower insertion loss than the micro-cell; and 3) The tensile strength of the fiber is well preserved. Many issues such as the LPG mode order, LPG cavity loss, sample cell design, ring-down pulse detection and analysis have been studied. As an example, the technique was applied to measure the spectral absorption of 1-octyne in decane solution and a detection limit of 0.62% 1-octyne was determined with the exist[ing] experimental setup, which is a fact or 2 better than the result using fiber taper.

Fiber loop ring-down spectroscopy with a long-period grating cavity

Cavity Ring-down spectroscopy is an absorption detection technique that makes the[sic]use of an optical cavity to realize a long effective optical path length through a sample and to render the measurement independent of intensity. These two features give the ring-down spectroscopy many advantages over traditional absorption techniques and allow it to measure chemicals present in trace amount. This thesis presents my study of fiber loop ring-down spectroscopy with a long-period grating (LPG) cavity as the sensing section. There are several advantages in this design: 1) It provides a relatively larger sensing area for the evanescent wave to interact with the environment when compared with a fiber taper and a D-shaped fiber; 2) The LPG cavity has a much lower insertion loss than the micro-cell; and 3) The tensile strength of the fiber is well preserved. Many issues such as the LPG mode order, LPG cavity loss, sample cell design, ring-down pulse detection and analysis have been studied. As an example, the technique was applied to measure the spectral absorption of 1-octyne in decane solution and a detection limit of 0.62% 1-octyne was determined with the exist[ing] experimental setup, which is a fact or 2 better than the result using fiber taper.

Multimode HMSIW-Based Bandpass Filter with Improved Selectivity for Fifth-Generation (5G) RF Front-Ends

This article presents the detailed theoretical, simulation, and experimental analysis of a half-mode substrate integrated waveguide (HMSIW)-based multimode wideband filter. A third-order, semicircular HMSIW filter is developed in this paper. A semicircular HMSIW cavity resonator is adopted to achieve wide band characteristics. A U-shaped slot (acts as a λ/4 stub) in the center of a semicircular HMSIW cavity resonator and L-shaped open-circuited stubs are used to improve the out-of-band response by generating multiple transmission zeros (TZs) in the stop-band region of the filter. The TZs on either side of the passband can be controlled by adjusting dimensions of a U-shaped slot and L-shaped open-circuited stubs. The proposed filter covers a wide fractional bandwidth, has a lower insertion loss value, and has multiple TZs (which improves the selectivity). The simulated response of filter agrees well with the measured data. The proposed HMSIW bandpass filter can be integrated with any planar wideband communication system circuit, thanks to its planar structure.

Development of Dielectric Material Enabling Low Insertion Loss of Organic Substrates at Various Operational Temperatures

With IP traffic increasing by 10-fold over the last decade, together with limitation and cost increase due to shrinking semiconductor nodes have led to requiring technological breakthrough in the packaging of semiconductor devices especially those used in high performance computing (HPC).This increase in IP traffic has led to requirement for higher data speed transmission in these devices, and consequently packaging technologies that enable those solutions such as 2.5D packaging utilizing silicon interposers. Furthermore, in recent years, increasing number of dies are placed in a single package for these devices thereby making the size of silicon interposers larger. Thus, the design of organic substrates used in these devices, are also becoming ever complex often with multiple layers with long trace lengths for routing increased number of IOs and allowing for power and signal control management. In order to facilitate the high speed data transmission requirement with longer trace lengths, stable low insertion loss design of organic substrates are becoming significantly important even when devices are exposed at elevated humidity or higher temperatures due to surrounding environment or from dies heating. Additionally, as silicon interposers are increasing in size, preventing stress build-up, which can cause cracking between the interposer and the organic substrate, is also becoming paramount. These requirements have led to innovative materials to be developed to enable organic substrates to have these properties. In this paper, we present a new dielectric build-up material for use in advanced organic substrates, by combining newly developed original resin with existing formulation technology that meet these criteria of enabling lower insertion loss with design that reduces deterioration even at elevated humidity and temperature, and furthermore having high crack resistance during temperature cycle testing.

Materials, Design, and Characteristics of Bulk Acoustic Wave Resonator: A Review

With the rapid commercialization of fifth generation (5G) technology in the world, the market demand for radio frequency (RF) filters continues to grow. Acoustic wave technology has been attracting great attention as one of the effective solutions for achieving high-performance RF filter operations while offering low cost and small device size. Compared with surface acoustic wave (SAW) resonators, bulk acoustic wave (BAW) resonators have more potential in fabricating high- quality RF filters because of their lower insertion loss and better selectivity in the middle and high frequency bands above 2.5 GHz. Here, we provide a comprehensive review about BAW resonator researches, including materials, structure designs, and characteristics. The basic principles and details of recently proposed BAW resonators are carefully investigated. The materials of poly-crystalline aluminum nitride (AlN), single crystal AlN, doped AlN, and electrode are also analyzed and compared. Common approaches to enhance the performance of BAW resonators, suppression of spurious mode, low temperature sensitivity, and tuning ability are introduced with discussions and suggestions for further improvement. Finally, by looking into the challenges of high frequency, wide bandwidth, miniaturization, and high power level, we provide clues to specific materials, structure designs, and RF integration technologies for BAW resonators.

Dual-Sense Circular Polarization Antenna Based on Reconfigurable Orthogonal Network

A novel circular polarization (CP) reconfigurable microstrip antenna is presented. The CP reconfigurable antenna is divided into three layers, composed of an annular radiating patch, ring slot, and reconfigurable orthogonal network (RON). The designed antenna is fed by dual vertical branches at the output port of the RON. By adjusting the bias voltage of the PIN switch loaded on the reconfigurable orthogonal network, the output phase can be changed, which means that the polarization direction of CP antenna is switchable. Simulation results show that the proposed feeding network provides constant phase difference and lower insertion loss for both states in the operating frequency band, thereby achieving good match and axial ratio characteristics either LHCP or RHCP state. Measured results show that the proposed antenna exhibits operational bandwidth of 1.2% with axial ratio below 3 dB and return loss above 10 dB in both polarized states. Good agreement between simulated and measured results is obtained.

Compact and Low Loss Microwave Idlers for Low Frequency Integrated Circuits

Two design methodologies for realization of low frequency (less than 20 GHz) compact and low loss microwave idlers have been proposed in this paper. Such idlers can be used for realizing low frequency higher order (6X or more) harmonic mixers or multipliers on monolithic integrated technology. Low frequency higher order harmonic mixers or multipliers are generally avoided due to higher losses and board space consumed by multiple idlers. The present proposed methods of idler design are based on realization of idlers by combining distributed microstrip transmission line and lumped components. The approach helps in transmitting the desired frequency with lower insertion loss and providing more rejection to the undesired frequencies. The design proposal has been demonstrated by designing an idler for 3 GHz LO side of a 6X harmonic MMIC mixer. This mixer utilizes 6th harmonic of the 3 GHz LO for generating 18 GHz output RF signal by frequency mixing. The idler for 3 GHz LO rejects dc, IF and selective even harmonics of LO; 6 GHz, 12 GHz and 18 GHz. On wafer test results of the developed 6X harmonic MMIC mixer has substantiated the idler design.

A low insertion loss low-pass filter based on single comb-shaped spoof surface plasmon polaritons

This paper presents a low insertion loss low-pass filter based on the spoof surface plasmon polariton (SSPP) with single comb-shape. Compared with traditional ones, the proposed filter provides lower insertion loss and return loss by optimizing the structural parameters of the mode conversion and SSPP parts. According to the measurement results, the average insertion loss of the fabricated filter is 0.41 dB and the return loss of which at the near-zero-hertz band is <−25.9 dB. The S parameter comparison result between the unoptimized and optimized filters demonstrates that the optimized filter provides lower insertion loss and return loss, smaller size, and better out-of-band rejection. The dispersion comparison result reveals the reasons behind the improved performances. The better performances of the optimized filter proves that breaking the regularity of traditional SSPP filters is beneficial to the filter's performances.