In general, Micropower Impulse Radar (MIR) depends on Ultra-Wideband (UWB) transmission systems. UWB technology can supply innovative new systems and products that have an obvious value for radar and communications uses. Important applications include bridge-deck inspection systems, ground penetrating radar, mine detection, and precise distance resolution for such things as liquid level measurement. Most of these UWB inspection and measurement methods have some unique qualities, which need to be pursued. Therefore, in considering changes to Part 15 the FCC needs to take into account the unique features of UWB technology. MIR is applicable to two general types of UWB systems: radar systems and communications systems. Currently LLNL and its licensees are focusing on radar or radar type systems. LLNL is evaluating MIR for specialized communication systems. MIR is a relatively low power technology. Therefore, MIR systems seem to have a low potential for causing harmful interference to other users of the spectrum since the transmitted signal is spread over a wide bandwidth, which results in a relatively low spectral power density.

/pdf/response-to-fcc-98-208-notice-of-inquiry-in-the-matter-of-3attixctl7.pdf

Response to FCC 98-208 notice of inquiry in the matter of revision of part 15 of the commission's rules regarding ultra-wideband transmission systems

This article presents a novel dual-polarized millimeter-wave (mm-Wave) patch antenna with bandpass filtering response. The proposed antenna consists of a differential-fed cross-shaped driven patch and four stacked parasitic patches. The combination of the stacked patches and the driven patch can be equivalent to a bandstop filtering circuit for generating a radiation null at the upper band edge. Besides, four additional shorted patches are added beside the cross-shaped driven patch to introduce another radiation null at the lower band edge. Moreover, by embedding a cross-shaped strip between these four stacked patches, the third radiation null is generated to further suppress the upper stopband. As a result, a quasi-elliptic bandpass response is realized without requiring extra filtering circuit. For demonstration, a prototype was fabricated with standard PCB process and measured. The prototype operates in the 5G band (24.25–29.5 GHz) and it has an impedance bandwidth of 20%. The out-of-band gain drops over 15 dB at 23 and 32.5 GHz, respectively, which exhibits high selectivity. These merits make the proposed antenna a good element candidate for the 5G mm-Wave massive MIMO applications to reduce the requirements of the filters in the mm-Wave RF front ends.

Millimeter-Wave Dual-Polarized Filtering Antenna for 5G Application

A structure of a compact ultra-wideband monopole antenna has been presented. The antenna consists of a microstrip-fed rectangle radiator as well as a ground plane with a rectangle slit and an L-shaped stub. The critical factor in achieving a small size is a careful design procedure involving numerical optimisation of all geometry parameters of the antenna aiming at explicit size reduction while maintaining acceptable electrical performance. The final design exhibits dimensions of only 9.45 × 18.5 mm and a footprint of 175 mm
 2
. Experimental validation and comparisons with competitive designs are also provided.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/el.2015.4432

Compact UWB monopole antenna for internet of things applications

Multi-beam antennas are critical components in future terrestrial and non-terrestrial wireless communications networks. The multiple beams produced by these antennas will enable dynamic interconnection of various terrestrial, airborne and space-borne network nodes. As the operating frequency increases to the high millimeter wave (mmWave) and terahertz (THz) bands for beyond 5G (B5G) and sixth-generation (6G) systems, quasi-optical techniques are expected to become dominant in the design of high gain multi-beam antennas. This paper presents a timely overview of the mainstream quasi-optical techniques employed in current and future multi-beam antennas. Their operating principles and design techniques along with those of various quasi-optical beamformers are presented. These include both conventional and advanced lens and reflector based configurations to realize high gain multiple beams at low cost and in small form factors. New research challenges and industry trends in the field, such as planar lenses based on transformation optics and metasurface-based transmitarrays, are discussed to foster further innovations in the microwave and antenna research community.

/pdf/quasi-optical-multi-beam-antenna-technologies-for-b5g-and-6g-1gpf5orbnv.pdf

Quasi-Optical Multi-Beam Antenna Technologies for B5G and 6G mmWave and THz Networks: A Review

A compact wideband four-way filtering PD is presented. The structure of the proposed device includes a pair of looped coupled-line structures to provide the needed power division to four output ports. Moreover, a pair of short-ended coupled-line stubs is used to introduce multiple transmission poles and transmission zeros for a sharp cut-off of the passband and high upper-stopband rejection. A detailed design procedure is shown to determine the initial design parameters. A prototype is designed, simulated and measured experimentally. The measured results show 56.5% bandwidth centered at 1.5 GHz with more than 15 dB upper-stopband rejection up to 4.15 GHz, more than 13 dB in-band isolation, and 15 dB return loss at all output ports.

Wideband Four-Way Filtering Power Divider With Sharp Selectivity and Wide Stopband Using Looped Coupled-Line Structures

An ultra-wideband (UWB) bandpass filter is proposed in this paper. The proposed structure composes of two pairs of microstrip short-circuited stubs which provide a microstrip-to-CPW transition, and a CPW resonator whose length is about half-guided-wavelength (λg/2) at 6.85GHz. A triple-mode UWB bandpass filter is produced using this microstrip-to-CPW transition structure. In order to suppress WLAN signals around 5.2/5.8GHz, a novel via-stub-loaded structure is designed. By adding this via-stub-loaded structure, a bandstop characteristic is formed as a notch-band whose position and bandwidth could be tuned easily. Simulation results indicate that the reflection loss is lower than -15dB in desired passband, and it also achieves a good performance of the notch-band around 5.2/5.8GHz. Finally, the proposed UWB bandpass filter is fabricated and measured. The measured results are in good agreement with simulated ones.

An ultra-wideband (UWB) bandpass filter with microstrip-to-CPW transition and a notch-band

On-chip passive distributed-element-based bandpass filters (BPFs) usually provide a decent stopband suppression across a limited bandwidth. To solve this drawback without adversely affecting other performance metrics, a simple but effective miniaturised BPF design approach is presented in this work. The proposed integrated BPF topology uses a combination of a coupled-inductor structure with a pair of metal–insulator–metal capacitors in a quasi-lumped-element realisation. To show the operational principles of this BPF approach, a simplified inductor–capacitor-equivalent circuit model is used for its theoretical analysis. From this analytical framework as an initial design guideline, a quasi-millimetre-wave BPF is designed and implemented in a standard 0.13 µm bipolar complementary–metal–oxide semiconductor technology. The measured results show that the developed BPF device has a centre frequency of 28 GHz with a 3 dB fractional bandwidth of 21% and minimum in-band power-insertion-loss level of 3.4 dB. The stopband suppression is higher than 25 dB beyond 45 GHz. The chip size, excluding the pads, is only 0.017 mm2 (0.06 × 0.284 mm2).

https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/iet-map.2019.0528

Miniaturised millimetre-wave BPF with broad stopband suppression in silicon–germanium technology

An ultra-wideband (UWB) phase shifter with wide range of differential phase shift is proposed. To achieve this performance, the design uses quarter wavelength parallel coupled lines combined with short-ended stub structure and an impedance transformer. The value of the differential phase can be adjusted through varying the coupling coefficient of the coupled lines along with the length and impedance of the short-ended stubs and transformer. The theory of operation for the proposed designs is explained. To validate the theory, two phase shifters are designed to realize 90° and 180° differential phase across the band 3.1-10.6 GHz with less than ±11° differential phase imbalance and less than 1.2 dB insertion loss.

Planar UWB phase shifter using parallel coupled lines combined with short-ended stubs and impedance transformer

A compact dual-band bandpass filter using a multi-mode resonator (MMR) is proposed. The MMR is composed of two pairs of short-ended coupled-lines, two pairs of open-ended coupled lines and four connecting transmission lines. The utilized structure enables creating five transmission zeros, resulting in controllable dual bands and wide upper-stopband suppression. By adjusting the related parameters of the MMR, a dual-band BPF is designed and modelled using a full-wave simulator. The two bands of the prototyped design are centred at 2.1 GHz and 3.6 GHz, with 3-dB fractional bandwidth of 15.6% and 9.2%, respectively. The overall size of the presented filter is only 0.2×0.2 guided-wavelength at the center frequency.

Compact dual-band bandpass filter using multi-mode resonator of short-ended and open-ended coupled lines

In this letter, a compact electromagnetic (EM) structure for miniaturized notch filter design in standard silicon technology is presented. Unlike prior-art on-chip bandstop filters, this filter configuration achieves sharp selectivity and large notch attenuation depth by producing a strong coupling between the top layer (i.e., resonating stub-loaded input-to-output direct path) and the bottom layer (i.e., two spiral-line grounded resonators). Moreover, as these vertically-stacked layers are broadside coupled, the physical footprint of the EM structure is significantly reduced. To demonstrate the proposed principle of notch filter, a simplified lossless behavioral model using ideal lumped elements is developed and verified. In addition, EM simulations are performed for parametric studies. As proof of concept, a prototype is fabricated in 0.13-<inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> bulk CMOS technology. The measurement results show that the designed filter exhibits a notch located at 19 GHz with an attenuation depth higher than 37 dB. The footprint, excluding the pads, is only 0.028 mm<sup>2</sup> (<inline-formula> <tex-math notation="LaTeX">${0.096}\times {0.296}$ </tex-math></inline-formula> mm<inline-formula> <tex-math notation="LaTeX">$^{{2}}$ </tex-math></inline-formula>).

He Zhu

Papers

An ultra-wideband (UWB) bandpass filter with microstrip-to-CPW transition and a notch-band

Miniaturised millimetre-wave BPF with broad stopband suppression in silicon–germanium technology

Planar UWB phase shifter using parallel coupled lines combined with short-ended stubs and impedance transformer

Compact dual-band bandpass filter using multi-mode resonator of short-ended and open-ended coupled lines

Miniaturized On-Chip Notch Filter With Sharp Selectivity and >35-dB Attenuation in 0.13-μm Bulk CMOS Technology