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We investigate and demonstrate the thermal crosstalk problem in integrated photonic circuits with metal and silicon doped heaters. Further, we illustrate that due to the localized heating effect, integrated doped heaters are out-performed in terms of thermal crosstalk as compared to integrated metal heaters. To mitigate thermal crosstalk and enhance phase tuning efficiency further, a CMOS compatible air-filled trench region is realized between the doped heater and the adjacent element. The performances of three fundamental building blocks of integrated photonic circuits, namely, a PN phase shifter, an optical attenuator, and a ring resonator, are tested by full-wave thermal, charge, and optical simulations. Additionally, the impact of thermal crosstalk on the performance of integrated PN phase shifters and optical attenuators is examined thoroughly. The proposed low crosstalk thermal phase shifters might be very beneficial for densely routed complex integrated photonic circuits like photonic transceivers for data centers, optical phased array antennas, and photonic reservoirs. INDEX TERMS Silicon on insulator (SOI), thermal crosstalk, phase shifter, integrated doped heaters, integrated optical attenuator, thermal switch, ring resonator.

A compact spurious free, quad‐band, band‐pass filter (BPF) having independently controllable and widely spaced frequency bands is proposed. The design consists of a basic BPF to which the authors introduce transmission zeros (TZs) in the frequency response using T‐shaped stubs loaded with a modified ring resonator (MRR) thereby creating the four passbands. This design results in very high band‐to‐band isolation. The TZs are obtained by transversal signal path cancellation and also due to the loaded T‐shaped stubs. The BPF consists of a stepped impedance low‐pass filter which provides spurious free out of band characteristics up to 20GHz. By changing the tapping position of the MRR, the frequencies of the TZs can be adjusted to get the desired pass band characteristics. The proposed quad‐band filter provides low‐insertion loss (<1dB) at the four passbands centred at 2.4, 5.1, 7.7 and 10.1GHz. The simulation results of the filter are verified experimentally.

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This article proposes model analysis of a microstrip leaky‐wave antenna for forward and backward scanning. Mode coupling and dual scan concept is introduced in this article with an inverted V‐section leaky‐wave antenna. The proposed design concept has been implemented on microstrip planar structure. An inverted V‐section has been therefore implemented which resulted in frequency scanning in forward and backward directions in the right‐hand (RH) region. The phenomenon has been observed within same frequency bandwidth of leaky‐wave region which is normally difficult to see in conventional leaky‐wave antennas. The article has also provided a circuit model analysis and design implementation explained by mode coupling theory. The proposed dual scanning leaky‐wave antenna (DSLWA) design is providing a wide impedance bandwidth in the Ku‐band and K‐band with high gain, reduced side lobe levels and high radiation efficiency.

This paper proposes an efficient transmission line modulation by using the bending technique to realize low profile leaky wave antennas in the Ku-band for frequency scanning and sensor applications. The paper focuses mainly on the bending effects of the transmission line in terms of the sharpness of edges. The right-hand/left-hand transmission line can be designed in the form of zig-zag pattern with sharp corners and only the right-hand transmission line in the form of sinusoidal patterns with smooth corners. In this presentation, we demonstrate that transmission lines of this kind can be used to realize highly efficient leaky wave antennas with broadband impedance matching and high gain characteristics in the Ku-band. Dispersion analysis and ladder network analysis have been performed for investigating the performance of the proposed designs. The sharpness of the bends periodically distributed along the body of the antenna has been used to our advantage for frequency scanning in the left-hand and right-hand quadrants at different frequencies. The proposed bending technique has been proven to be instrumental in achieving the desired characteristics of low profile leaky wave antennas.

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