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An RF phase detector employing an analog integrator is proposed for active phased array antenna system. The RF phase detector, consisting of an analog integrator, a mixer and a divider can realize both fast and highly accurate detection at the same time. By setting the integral time of the analog integrator as integral multiple of the half cycle of RF signal, the variation of output voltage due to...
A power sensor operating at low dc power with cyclic logarithmic amplifier is proposed in this paper. The input signal passes RC low pass filter firstly, and then feeds to a cyclic logarithmic amplifier to have linear-in-dB output. DC offset and flicker noise are eliminated by using a chopper. It is fabricated by TSMC 0.18 um 1P6M CMOS process. For DC current input, the dynamic range is 31-dB, with...
For the tunable RF FEMs or Antennas, analysis on optimal design of tunable capacitors which consist of MIM capacitors and RF CMOS switches is performed in terms of quality factor, tuning ratio and harmonics. To handle up to +36dBm RF signal, the Stacked-FET and series Capacitor-Transistor-Capacitor (CTC) configuration applied Coupled-Bias(CB) are proposed, which in addition to being high-linearity...
In this work, gap waveguide based packaging technique is used to improve the isolation among critical microwave circuit components such as high gain amplifier chain. Amplifier chains at Ka-band were tested for a stable forward gain and it was found that-with gap waveguide packaging, 65∼70dB of forward gain is achievable without the problem of self-resonance. Apart from the new packaging technique,...
In this paper, two novel substrate integrated waveguide (SIW) transmitters, in Ku band and K band respectively, based on low-temperature co-fired ceramic (LTCC) technology, are proposed. A Ku band SIW filter with elliptic response is located in the input of the Ku band single channel transmitter, as well as SIW transmission lines embedded in LTCC substrate for good isolation with DC bias. A SIW divider...
A compact planar phase shifter with ultra-wideband (UWB) performance and wide range of differential phase shift is proposed. To achieve that performance, the device uses broadside electromagnetic coupling between top and bottom microstrip patches via a slot located in the middle layer that forms the ground plane. Two short-ended stubs are connected to the microstrip patches to expand the range of...
This paper describes an investigation into a novel miniaturized microwave matched band-stop filter with pseudo-infinite attenuation for the enhancement of wireless link on floating production storage and offloading (FPSO) vessels. The proposed method is capable to produce almost infinite attenuation even with very low Q resonator and is suitably used to suppress very high power interference signal...
A novel design of compact negative group delay circuit (NGDC) using U-shaped defected ground structure (DGS) is presented in this paper. The required group delay (GD) time can be controlled by an external resistor connected across the DGS slot. For experimental verification, a single stage NGDC is designed, fabricated, and compared with a circuit simulation. To enhance NGD bandwidth, two stages NGDC...
A new direct coupling matrix synthesis approach for bandpass filters with extracted-poles is presented. Different from existing synthesis methods, the extracted-pole sections and the remaining cross-coupled resonators are synthesized in a unified approach. As a result, the coupling matrix synthesized contains both resonant and non-resonant nodes. Another distinct feature of the coupling matrix synthesized...
Important parameters of waveguide diplexer components as lowpass filter and combiner, have been improved. Concave shaping of vertical walls of a corrugated filter decreases reflection coefficients by 10 dB in the 14.5–15.35 GHz band. Placement of inserts at the antenna port of a combiner increases bandwidth by more than 50%.
This paper reviews recent progress on nonreciprocal CRLH metamaterials with nonreciprocal phase constants and their applications to beam-scanning antennas. The nonreciprocal CRLH metamaterials show positive and negative refractive indices at the same frequency, selection of which depends on directions of the transmitted power. Traveling wave resonators with variable size and phase gradient of the...
AMCs, EBGs and other surface-based metamaterials are known to have narrow bandwidths. However, when they are used to generate stopbands for parallel-plate modes, the bandwidth can be very large. This characteristic is used in the gap waveguide technology that was invented in 2008, based on old research on soft and hard surfaces. The gap waveguide technology can be used to package microstrip and CPW...
A leaky wave antenna(LWA) is studied by using dispersion diagram. The advantages are a simple design, a low profile, and high boresight directivity over the frequency bands. Moreover, the radiation properties of the leaky wave are investigated by means of the theoretical analysis by using dispersion properties of a unit cell for the LWA. The measured and predicted results verify the performance of...
In this paper, it is presented that novel and compact filters and channel combiners are developed for a lighter multi-channel vehicular transceiver working at an X-band and a Ku-band as high frequencies instead of bulky metallic waveguides. The components are in the form of so-called substrate integrated waveguide(SIW) as planar layered structures. For the purpose of reducing the physical sizes of...
This paper proposes novel antenna arrangements which improve the channel capacity for 4×4 multiple-input multiple-output (MIMO) system in line-of-sight (LOS) environment. It is shown that the channel matrix is unitary matrix by the proposed antenna arrangement and the high channel capacity is obtained by the proposed antenna arrangement with directional antennas even if the multipath signals in indoor...
A MIMO antenna with decoupling network for headset applications is proposed. The performance of the antenna is investigated when the antenna is placed on a head phantom. The antenna consists of two monopole type radiators and a decoupling network that improves the isolation between two radiators. The antenna on the human head phantom covers ISM band and the isolation exceeds 20 dB. Because the ECC...
A multiband MIMO antenna for a 4G mobile terminal is proposed. The antenna structure consists of a multiband main antenna element, a printed inverted-L subantenna element operating in the higher 2.5 GHz bands, and a wideband loop sub-antenna element working in lower 0.9 GHz band. In order to improve the isolation and ECC characteristics of the proposed MIMO antenna, each element is located at a different...
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